UFOpaedia - User contributions [en]

Accuracy vs TU Efficiency

2016-09-18T01:08:05Z

Ant 222:

In almost every case (Rockets are the exception), Snap fire is a more efficient use of TUs than Aimed fire. This means Aimed fire is not useful apart from certain specialised activities.

=Proposal=

Would it be unreasonable to correct the TU and/or accuracy values of weapons, so that if we call the efficiency (hits per unit of time)

K = accuracy/TUs

and we have

Kai (K - Aimed)
Ksn (K - Snap)

we correct the game tables to ensure that for any given weapon:

Kai > Ksn

In English, we are saying that extra time spent on aiming is no less useful than time spent snap firing. Or, if I spend twice as long on an aimed shot than on a snap shot, my chance of hitting should be doubled.

( In an unmodified game, this relationship does not hold, for all cases except Rockets. )

The purpose of this modification would be to ensure that, in terms of delivering hits to the target per unit of time, Aimed fire is more effective than Snap fire, which in turn is more effective than Auto fire.

Otherwise there are few reasons not always use the fastest available fire rate.

(3 reasons I can think of are:

* Conserving ammo - often of minor importance, except with single launcher rounds (Rockets etc), especially rare/expensive ones such as Blaster Bombs.
* Avoiding "collateral damage" to friendly troops, civilians, or valuable recoverable items
* "First shot kill" - killing the target before it can reaction-fire

But for general combat, there is often no reason to prefer Aimed fire over Snap, or Snap over Auto.

=Discussion=

Analysis of 20th century battles showed that ordinary soldiers were more effective at killing the enemy when they were given automatic weapons. Resistance to equipping troops with full auto small arms as standard was mainly on ammunition cost grounds (as well as conservatism). This was further refined by studies showing that a burst mode (as used in XCom) was optimum.

However, this was true only for the ordinary troops, who were found to be too unsettled by combat to fire in a controlled fashion. For the minority who had the presence of mind to fire under control, taking slow, carefully aimed shots was more effective and this is where the bulk of the overall effective firepower of an entire formation would come from.

Now, which group do we think XCom soldiers fall into?

[[User:Spike|Spike]] 13:28, 10 November 2008 (CST)

:X-COM soldiers are selected as the best available volunteers from the various militaries of the funding nations, according to backstory. Thus they'd probably be more geared towards the latter class. However, given the...shall we say...less-than-ideal stats of some recruits, its clear that even then that's not going to hold. Bravery would probably be one of the main stats applicable to this argument. It should also be noted that X-COM soldiers are fighting a completely different war, one which could well make most regular soldiers break down from the stress alone. Think about it, for the first half of the game, at least, X-COM soldiers are out-equipped, fighting ALIENS, some 4 times thier own size, who can kill them in one glancing hit from a PLASMA weapon, while they themselves have trouble even hurting some of them, and whom are coming from OUTER SPACE in UFOs they can't scratch on the ground and which can VAPORIZE F-22s(or whatever the Interceptor is). That's not even mentioning the funding issues, terror attacks, or psychological scarring. And every time the Skyranger goes out, they can pretty much count on the fact that at least 2 or 3 of the people they're inside it with will be coming back to base in a body bag. This is liable to put ANYONE, even a battle-hardened combat vet of a normal earth military, off balance, at the very least. Which can be seen in how rapidly X-COM recruits tend to panic when things go bad. Overall troop morale would be one X-COM's (or any such organization's) greatest problems.

:As for the use of aiming/snap/auto, it's basically been established that in UFO, auto reigns supreme. Whereas in TFTD, auto fire is only available on a handful of weapons, with horrendous accuracy for it, and usually with a fairly small clip. I don't know how many Aquanauts I've had run dry on ammo at a critical moment because I used the Jet Harpoon's Autofire too liberally(read: use at all) TFTD's weapons, however, have awesome Aimed accuracy stats, swinging it in the opposite direction of UFO; aimed is the prefered fire of choice. Also, perhaps use Scout/Sniper some more if you want to use Aimed mode; it increases overall safety. :) [[User:Arrow Quivershaft|Arrow Quivershaft]] 13:50, 10 November 2008 (CST)

Good points there AQ. It's probably reasonable (for many reasons) to treat XCom's "elite" recruits as effectively rookies when tangling with aliens and alien weapons.

Thinking about auto modes, actually it does make sense that they have better firepower than the other modes. Otherwise why would they be used at all? Auto should be more effective per unit of time, less effective per unit of ammo - which it is.

That being the case, a more moderate proposal would be to tweak the game to ensure that Kai > Ksn, i.e. Aimed fire is more effective than Snap, per unit of time. Surely that is just common sense? Otherwise there is very little reason ever to Aim.

By the way, could you expand on your thoughts about Scout/Sniper? I'm not sure I understand how this tactic gives greater weight to Aimed Fire. Are there any considerations apart from reducing friendly fire and enemy reaction fire?

[[User:Spike|Spike]] 09:32, 11 November 2008 (CST)

: One additional benefit I can see for using the scout/sniper strategy other than the benefits already mentioned would be the fact that the sniper will not have to move as much, if at all. Therefore the sniper will have more TUs available to make aimed shots. Obviously this means nothing for some weapons that can only be fired once per turn on aimed, but for weapons that can be aimed several times, then every extra TU helps. Just as snaps and auto shots bank on extra attempts to improve their odds of success, the same can apply to aimed shots too. -[[User:NKF|NKF]] 22:38, 12 November 2008 (CST)

In real combat, both quick and carefully aimed shots are useful depending on the situation, for at least two reasons. In situations such as an ambush, when the target is unaware of the firer, it is beneficial to hit it with the first shot, regardless or how long it may take to aim precisely, because after that the firer's position, if only approximately, will be made known to the enemy, who will then be prepared for fire from the same quarter and will seek cover and possibly fire back. This consideration can hardly be accounted for in the classic X-COM (but must be in the games it inspired).

The second reason is that snap shots are more effective at close range and aimed ones at long range. It happens because at short range the dispersion cone is much smaller than the target's angular area and aiming consists of pointing the weapon roughly at the target without the use of sights. The hit change is near 100% so the one who shorts first is the winner. At long range, however, the situation is reversed. The weapon must be aligned carefully to point at the small target and stabilized to narrow down the dispersion cone. The effect of distance is not uniform across all ranges but follows the behavior of the quantiles of the normal distribution:

[[File:HitChance1d.png|||center|||||One-dimensinal formula for hit chance]]

where Φ is the [https://en.wikipedia.org/wiki/Normal_distribution#Cumulative_distribution_function cumulative normal distribution function], ''d'' the distance to the target, and ''r'' the target's characteristic radius as projected in the firer's direction. The standard deviation σ determines the opening angle of the dispersion cone and thus the accuracy of the shot.
Here are the graphs for three different accuracies:

[[File:HitChanceVsDistance.png|center|Hit chance vs. distance]]

Precise aiming takes a certain time determined by the weapon and the firer, after which accuracy reaches a plateau and then starts to degrade due to fatigue. During the effective aiming stage the rate of accuracy increase is highest at the beginning and becomes lower at it approaches the plateau, but in the end the probability of defeating a remote target is improved out of all proportion with regard to the time spent aiming.

That being said, I don't think serious improvement is possible unless someone can change the hit-chance formula so that it will approximate, if loosely, the varying effect of distance at different ranges described above. As distance increases the effectiveness of auto- and snap shots should become lower compared to that of an aimed shot. [[User:Ant 222|Ant 222]] ([[User talk:Ant 222|talk]]) 15:28, 1 September 2016 (UTC)

:UFO:EU does actually use dispersion cones, FYI. The displayed accuracy of the shot is the chance that it will use the narrower "hit" dispersion cone instead of the wider "miss" dispersion cone, but "hits" can miss (usually due to cover, such as trying to hit an alien in a building through a window, but at long ranges true misses are possible against small targets) and "misses" can hit (most obviously at point-blank range). The size of the cones is also adjusted based on that accuracy, so the dispersion of a "miss" from a shot with 10% displayed accuracy is much larger than that of a "miss" from a shot with 99% displayed accuracy. So the "improvement" you want is already there to some extent. [[User:Magic9mushroom|Magic9mushroom]] ([[User talk:Magic9mushroom|talk]]) 00:58, 2 September 2016 (UTC)

I fear that we disagree about the term ''dispersion cone''. I understand it as the normally distributed direction of the projectile, so that each shot is modeled by a single dispersion cone, which describes all the possible outcomes with their corresponding probabilities. This interpretation leaves no place for two dispersion cones. If UFO:EU chooses the wider or the narrower of some two dispersion cones depending on accuracy, then it largely defeats the cause of the normal model with respect to the non-linear dependency on distance, for the choice of either the ''hit'' or the ''miss'' dispersion cone is the definitive factor, whereas the subsequent modeling with the chosen cone is only secondary, because the ''hit'' cone almost always results in a hit and the ''miss'' one in a miss.

Is the algorithm that you have described documented anywhere? [[Accuracy_formula]] does not mention it and seems to imply a single dispersion cone per shot...[[User:Ant 222|Ant 222]] ([[User talk:Ant 222|talk]]) 17:08, 2 September 2016 (UTC)

:[[User_talk:Bomb_Bloke:Firing_Accuracy|Here]]. And as I said, "misses" actually hit fairly often at close range, and "hits" failing to hit isn't unheard of. [[User:Magic9mushroom|Magic9mushroom]] ([[User talk:Magic9mushroom|talk]]) 22:20, 2 September 2016 (UTC)

Thanks for the link. The problem with the algorithm is that two of its three stages are physically meaningless. First—the random choice of the equation for the divergence factor, and second—its high dependency on an another random number within the chosen equation. For any given combination of the firer's stats, the weapon's stats, and shot type divergence should be strictly constant, and the very generation of a single angle distributed normally with the aforesaid divergence (which I take to be a measure of dispersion) should be the only source of randomness, whereas that algorithm severely diminishes the role of the normal-distribution model by introducing way too much randomness in the determination of its parameters.

Nobody seems to have understood that what [[User:Bomb Bloke]] so painstakingly logged is actually direct samplings of the cumulative distribution function of angular deviation. He need only plot his data correctly to see that.[[User:Ant 222|Ant 222]] ([[User talk:Ant 222|talk]]) 01:08, 18 September 2016 (UTC)

=Data Analysis=

OK I did some quantitative analysis and the results are not good. The ''only'' weapons for which Aimed Fire has better efficiency of Accuracy::TU compared to Snap Fire, are Rockets and the Rocket Tank. In the notation above, there are only 3 weapons for which Kai > Ksn. In most cases, Snap fire is ''considerably'' more efficient - typically around 70% more efficient. Even for the Rocket weapons, Aimed Fire is only 25% (i.e. one-quarter) more effective. For all other weapons, including HWP and alien built-in attacks, snap fire is more efficient (in terms of generating hits on the target per unit of time). Obviously it is not good to have a game mechanic that is barely used because it has no real usefulness. I guess the proposal would be to raise the efficiency level of Aimed fire, and leave Snap fire where it is now. This would be the least unbalancing change, since Aimed fire is rarely used now, and even if it was more effective, it is tactically problematic to use because of the high TU cost. Even if you adjusted all weapons so that Aimed fire was 25% more efficient than Snap fire, I doubt that would be much incentive to use Aimed fire. 50% efficiency gain would be more likely to actually create real tactical alternatives that would get used by players in the game. By way of example, this would mean increasing the based Aimed accuracy of a Laser Rifle to around 200% (for 50% TU cost; vs Snap at 65% Accuracy for 25% TU cost). [[User:Spike|Spike]] 18:17, 6 December 2008 (CST)

:There's other measures of efficiency, as well. For example, with any explosive munition, Aimed fire gets a second chance because as a general rule, you don't want an explosive going off in the wrong place. Particularly true with the Large Rocket and HC-HE. (Also somewhat of an issue with the Small Launcher, but it's mitigated because affected units are only stunned, not killed.) On a similar note, aimed is nice in Scout-Sniper so you don't shoot the spotter(The aimed guy doesn't have to move much so has lots of TUs for aimed fire.) [[User:Arrow Quivershaft|Arrow Quivershaft]] 18:27, 6 December 2008 (CST)

:: Yes I definitely agree there are non-firepower benefits of Aimed fire, that are already present in the game. As you say these include control of collateral damage (with HE or with exposed scouts), and ammo-efficient (also "opportunity-efficient") use of single-shot weapons. Fair point! Can we list out all of the non-firepower benefits? I'm really trying hard to see if it's possible to make the case that Aimed fire is not pointless, from a game design / game balance point of view. [[User:Spike|Spike]] 19:21, 6 December 2008 (CST)

:Well, one big thing is that reloading a weapon takes 15 TUs flat. This is actually a fair bit. For a rookie, it can be anywhere from 1/4th to almost 1/3rd of his full TU allotment, whereas its just below 1/5th for a top-level veteran. Any weapon with a small clip is going to require reloading on a regular basis if repeated snap fire is used. Anything with a 1-round clip counts, any arguably, so does the Heavy Cannon. (Though the Blaster Launcher has no mode other than Aimed, so is only included for example). The more ammo you use, the more you need to carry, thus the more space you need in the transport.
:A single soldier can carry, at most, 5 rockets, 7 Blaster Bombs, 66 Heavy Cannon shots(11 clips), or 25 Small Launcher rounds. (These numbers do not take into account Strength limitations, or use of the Item Stacking bug. Also note that there's no reason you should need that many Small Launcher rounds.) Consider how many spaces this is on the transport, for one. Then multiply this across the number of associated weapons...you hit 80 pretty fast. Using lots of ammo means less room on the transport for other gear. Also consider how weighted down the soldier is. A soldier hauling around a rocket launcher and 4 reloads is carrying 50 units of weight, leaving not much room for other gear.
:The collateral damage is an issue that needs to be watched for, of course. Snap-firing a Large Rocket can kill large portions of your team if not done properly. Even if none of your soldiers are killed, you may destroy valuable equipment if not careful. (Especially true near UFO power sources!) And at range, snap fire's path can intersect the position of a soldier.
:Cost is yet another. In particular, in the case of the Small Launcher, ammunition requires Elerium to manufacture. And Large Rockets don't come too cheap if you're firing them off willy-nilly.
:And finally, when dealing with the tanks, the Ammo problem is even worse...you CAN'T reload in the middle of battle; you get one magazine and that's it. (This is only truly relevant for the Rocket Tank and Fusion Hovertank.) Plus ammo is even more expensive!
:There was another idea I had, but it escapes me currently. Still, I think this is a fairly comprehensive list. [[User:Arrow Quivershaft|Arrow Quivershaft]] 20:18, 6 December 2008 (CST)

=TU Efficiency Table=

The table below shows the extent to which Aimed fire is less efficient than Snap fire. A value of 50% would mean Aimed fire is half as efficient (in terms of accuracy:TU) as Snap fire. The table also shows what the required value of Aimed Accuracy % would need to be increased to, in order to make Aimed fire as efficient (100%) as Snap fire, or 125% as efficient, or 150% as efficient.

See also the [[Firepower Tables]] which show how ineffective Aimed fire is in terms of damage-on-target. The root cause of the damage-on-target inefficiency, is this TU inefficiency.

<table {{StdCenterTable}} class="sortable">
<caption><b>Aimed vs Snap fire - Accuracy::TU Efficiency<br>with corrective values for Aimed Accuracy
</b></caption>
<tr {{StdDescTable_Heading}}>
<th>Weapon</th><th>Aim Acc%</th><th>Aim:Snap</th><th>100%</th><th>125%</th><th>150%</th>
<tr><td>Pistol</td><td>78</td><td>78%</td><td>100</td><td>125</td><td>150</td></tr>
<tr><td>Rifle</td><td>110</td><td>57%</td><td>192</td><td>240</td><td>288</td></tr>
<tr><td>HC - AP</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>HC - HE</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>AC - AP</td><td>82</td><td>60%</td><td>136</td><td>170</td><td>204</td></tr>
<tr><td>AC - HE</td><td>82</td><td>60%</td><td>136</td><td>170</td><td>204</td></tr>
<tr><td>RocketSm</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>RocketLg</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>LaserP</td><td>68</td><td>62%</td><td>110</td><td>138</td><td>165</td></tr>
<tr><td>LaserR</td><td>100</td><td>77%</td><td>130</td><td>163</td><td>195</td></tr>
<tr><td>HvyLas</td><td>84</td><td>74%</td><td>114</td><td>142</td><td>170</td></tr>
<tr><td>HvyLas (XCU)</td><td>110</td><td>81%</td><td>136</td><td>170</td><td>205</td></tr>
<tr><td>PlasmaP</td><td>85</td><td>65%</td><td>130</td><td>163</td><td>195</td></tr>
<tr><td>PlasmaR</td><td>100</td><td>58%</td><td>172</td><td>215</td><td>258</td></tr>
<tr><td>HvyPlas</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Blast Bmb</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td></tr>
<tr><td>Stun Bmb</td><td>110</td><td>90%</td><td>122</td><td>152</td><td>183</td></tr>
<tr><td>Tk Cannon</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>Tk Rocket</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>Tk Laser</td><td>85</td><td>75%</td><td>114</td><td>142</td><td>170</td></tr>
<tr><td>Tk Plasma</td><td>100</td><td>59%</td><td>170</td><td>213</td><td>255</td></tr>
<tr><td>Tk Fusion</td><td>100</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td></tr>
<tr><td>Cyberdisc</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Celatid</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Sectopod</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>

</table>

=TU Efficiency Mods=

The following replacement OBDATA.DAT files implement the principle that Aimed fire should not be less efficient than Snap fire. To use these, make a safe copy of your original OBDATA.DAT in the GEODATA folder, then replace it with one of these files. You should see the new improved base accuracies (and in some cases reduced TU costs) in the in-game UFOPaedia.

* [[Media:OBDTU100.DAT]] fixes Aimed fire so it is exactly as efficient as Snap fire.
* [[Media:OBDTU125.DAT]] fixes Aimed fire so it is 125% more efficient then Snap fire. This is the same ratio between Snap and Aimed fire that exists for Rockets.
* [[Media:OBDTU150.DAT]] fixes Aimed fire so it is 150% more efficient then Snap fire. This is probably over-powerful, and too unbalancing in the other direction. Also, in some cases (Rifle and Plasma Rifle) it is necessary to reduce the TU cost of Aimed fire slightly, as otherwise Accuracy would need to be raised above 255% (not possible as it is held in a single unsigned byte).

[[Category:Enemy Unknown/UFO Defense]]

File talk:BBFiringPointTest4.png

2016-09-18T00:21:43Z

Ant 222:

OK, I've got to say, I can't interpret this graph. There is just not enough information. What are the X and Y axis variables? Is the Y axis degrees (degrees of deflection from "true path")? If so, what's the X axis? Is this a histogram? If it was a histogram I would expect degrees of deflection on the X axis, maybe positive and negative with zero at the centre, and then frequency on the Y axis. But this seems to be some kind of inversion of a histogram. I am confused! Help most appreciated! [[User:Spike|Spike]] 16:33, 14 April 2009 (EDT)

----

It's not really a histogram, though it's similar to one in purpose. I can't remember what it is. It may be that a histogram would've been a better way to render the results.

The Y axis represents angles. The higher the line is at any given point, the more of an angle that point of the line represents. Note that an angle of 0 (where the shot was fired perfectly in a straight forward direction) is represented when the line hits the bottom of the Y axis.

The longer the line stays at a given height while travelling along the X axis, the more shots hit that particular angle. Keep in mind we're talking at least a thousand shots represented per graph - I wasn't sure how to label the X axis to portray this, so I didn't...

Probably didn't explain that very well on the talk page. Where the line hits the bottom of the graph, that's when shots were going straight. The area to the left of that point represents shots that went off to the left, and the area to the right represents shots that went off to the right.

You're probably thinking about now that the graph should look something more like what x^3 would look like ([http://www.coolmath.com/graphit you can check that here if need be]), because half the angles should really be "positive" and the other half should be "negative" (depending on whether they went to the left/right of the trooper). I decided to call them all positive and just bung them on opposing sides of the line.

So to make the graph, I sorted the entire list of angles in ascending order, then did a line graph of their absolute values.

Note that if you had the same chance of hitting any given angle within your maximum range, the graph would've ended up looking like a V (or a / if I'd used a negative axis).

Er, hopefully you'll be able to work out what I'm on about by graphing the test results for yourself. :)

- [[User:Bomb Bloke|Bomb Bloke]] 22:52, 14 April 2009 (EDT)

----

May I venture an answer by saying that if one rotates the graph 90 degrees CCW and then flips its upper half horizontally around the point where it joins the lower half it shall become the [https://en.wikipedia.org/wiki/Cumulative_distribution_function cumulative distribution function] of angular deviation, which is very amenable to statistical analysis? To demonstrate—take the V that you mentioned. After rotation it will become >, and flipping its upper half will produce /, which is the (cumulative) distribution function of the normal distribution. To avoid confusion, could you re-plot the graphs in the manner described? You will only have to use the raw (signed) angle instead of its absolute value and exchange the axes to get a sigmoid increasing from left to right. [[User:Ant 222|Ant 222]] ([[User talk:Ant 222|talk]]) 00:21, 18 September 2016 (UTC)

Accuracy vs TU Efficiency

2016-09-02T21:38:17Z

Ant 222: /* Discussion */

In almost every case (Rockets are the exception), Snap fire is a more efficient use of TUs than Aimed fire. This means Aimed fire is not useful apart from certain specialised activities.

=Proposal=

Would it be unreasonable to correct the TU and/or accuracy values of weapons, so that if we call the efficiency (hits per unit of time)

K = accuracy/TUs

and we have

Kai (K - Aimed)
Ksn (K - Snap)

we correct the game tables to ensure that for any given weapon:

Kai > Ksn

In English, we are saying that extra time spent on aiming is no less useful than time spent snap firing. Or, if I spend twice as long on an aimed shot than on a snap shot, my chance of hitting should be doubled.

( In an unmodified game, this relationship does not hold, for all cases except Rockets. )

The purpose of this modification would be to ensure that, in terms of delivering hits to the target per unit of time, Aimed fire is more effective than Snap fire, which in turn is more effective than Auto fire.

Otherwise there are few reasons not always use the fastest available fire rate.

(3 reasons I can think of are:

* Conserving ammo - often of minor importance, except with single launcher rounds (Rockets etc), especially rare/expensive ones such as Blaster Bombs.
* Avoiding "collateral damage" to friendly troops, civilians, or valuable recoverable items
* "First shot kill" - killing the target before it can reaction-fire

But for general combat, there is often no reason to prefer Aimed fire over Snap, or Snap over Auto.

=Discussion=

Analysis of 20th century battles showed that ordinary soldiers were more effective at killing the enemy when they were given automatic weapons. Resistance to equipping troops with full auto small arms as standard was mainly on ammunition cost grounds (as well as conservatism). This was further refined by studies showing that a burst mode (as used in XCom) was optimum.

However, this was true only for the ordinary troops, who were found to be too unsettled by combat to fire in a controlled fashion. For the minority who had the presence of mind to fire under control, taking slow, carefully aimed shots was more effective and this is where the bulk of the overall effective firepower of an entire formation would come from.

Now, which group do we think XCom soldiers fall into?

[[User:Spike|Spike]] 13:28, 10 November 2008 (CST)

:X-COM soldiers are selected as the best available volunteers from the various militaries of the funding nations, according to backstory. Thus they'd probably be more geared towards the latter class. However, given the...shall we say...less-than-ideal stats of some recruits, its clear that even then that's not going to hold. Bravery would probably be one of the main stats applicable to this argument. It should also be noted that X-COM soldiers are fighting a completely different war, one which could well make most regular soldiers break down from the stress alone. Think about it, for the first half of the game, at least, X-COM soldiers are out-equipped, fighting ALIENS, some 4 times thier own size, who can kill them in one glancing hit from a PLASMA weapon, while they themselves have trouble even hurting some of them, and whom are coming from OUTER SPACE in UFOs they can't scratch on the ground and which can VAPORIZE F-22s(or whatever the Interceptor is). That's not even mentioning the funding issues, terror attacks, or psychological scarring. And every time the Skyranger goes out, they can pretty much count on the fact that at least 2 or 3 of the people they're inside it with will be coming back to base in a body bag. This is liable to put ANYONE, even a battle-hardened combat vet of a normal earth military, off balance, at the very least. Which can be seen in how rapidly X-COM recruits tend to panic when things go bad. Overall troop morale would be one X-COM's (or any such organization's) greatest problems.

:As for the use of aiming/snap/auto, it's basically been established that in UFO, auto reigns supreme. Whereas in TFTD, auto fire is only available on a handful of weapons, with horrendous accuracy for it, and usually with a fairly small clip. I don't know how many Aquanauts I've had run dry on ammo at a critical moment because I used the Jet Harpoon's Autofire too liberally(read: use at all) TFTD's weapons, however, have awesome Aimed accuracy stats, swinging it in the opposite direction of UFO; aimed is the prefered fire of choice. Also, perhaps use Scout/Sniper some more if you want to use Aimed mode; it increases overall safety. :) [[User:Arrow Quivershaft|Arrow Quivershaft]] 13:50, 10 November 2008 (CST)

Good points there AQ. It's probably reasonable (for many reasons) to treat XCom's "elite" recruits as effectively rookies when tangling with aliens and alien weapons.

Thinking about auto modes, actually it does make sense that they have better firepower than the other modes. Otherwise why would they be used at all? Auto should be more effective per unit of time, less effective per unit of ammo - which it is.

That being the case, a more moderate proposal would be to tweak the game to ensure that Kai > Ksn, i.e. Aimed fire is more effective than Snap, per unit of time. Surely that is just common sense? Otherwise there is very little reason ever to Aim.

By the way, could you expand on your thoughts about Scout/Sniper? I'm not sure I understand how this tactic gives greater weight to Aimed Fire. Are there any considerations apart from reducing friendly fire and enemy reaction fire?

[[User:Spike|Spike]] 09:32, 11 November 2008 (CST)

: One additional benefit I can see for using the scout/sniper strategy other than the benefits already mentioned would be the fact that the sniper will not have to move as much, if at all. Therefore the sniper will have more TUs available to make aimed shots. Obviously this means nothing for some weapons that can only be fired once per turn on aimed, but for weapons that can be aimed several times, then every extra TU helps. Just as snaps and auto shots bank on extra attempts to improve their odds of success, the same can apply to aimed shots too. -[[User:NKF|NKF]] 22:38, 12 November 2008 (CST)

In real combat, both quick and carefully aimed shots are useful depending on the situation, for at least two reasons. In situations such as an ambush, when the target is unaware of the firer, it is beneficial to hit it with the first shot, regardless or how long it may take to aim precisely, because after that the firer's position, if only approximately, will be made known to the enemy, who will then be prepared for fire from the same quarter and will seek cover and possibly fire back. This consideration can hardly be accounted for in the classic X-COM (but must be in the games it inspired).

The second reason is that snap shots are more effective at close range and aimed ones at long range. It happens because at short range the dispersion cone is much smaller than the target's angular area and aiming consists of pointing the weapon roughly at the target without the use of sights. The hit change is near 100% so the one who shorts first is the winner. At long range, however, the situation is reversed. The weapon must be aligned carefully to point at the small target and stabilized to narrow down the dispersion cone. The effect of distance is not uniform across all ranges but follows the behavior of the quantiles of the normal distribution:

[[File:HitChance1d.png|||center|||||One-dimensinal formula for hit chance]]

where Φ is the [https://en.wikipedia.org/wiki/Normal_distribution#Cumulative_distribution_function cumulative normal distribution function], ''d'' the distance to the target, and ''r'' the target's characteristic radius as projected in the firer's direction. The standard deviation σ determines the opening angle of the dispersion cone and thus the accuracy of the shot.
Here are the graphs for three different accuracies:

[[File:HitChanceVsDistance.png|center|Hit chance vs. distance]]

Precise aiming takes a certain time determined by the weapon and the firer, after which accuracy reaches a plateau and then starts to degrade due to fatigue. During the effective aiming stage the rate of accuracy increase is highest at the beginning and becomes lower at it approaches the plateau, but in the end the probability of defeating a remote target is improved out of all proportion with regard to the time spent aiming.

That being said, I don't think serious improvement is possible unless someone can change the hit-chance formula so that it will approximate, if loosely, the varying effect of distance at different ranges described above. As distance increases the effectiveness of auto- and snap shots should become lower compared to that of an aimed shot. [[User:Ant 222|Ant 222]] ([[User talk:Ant 222|talk]]) 15:28, 1 September 2016 (UTC)

:UFO:EU does actually use dispersion cones, FYI. The displayed accuracy of the shot is the chance that it will use the narrower "hit" dispersion cone instead of the wider "miss" dispersion cone, but "hits" can miss (usually due to cover, such as trying to hit an alien in a building through a window, but at long ranges true misses are possible against small targets) and "misses" can hit (most obviously at point-blank range). The size of the cones is also adjusted based on that accuracy, so the dispersion of a "miss" from a shot with 10% displayed accuracy is much larger than that of a "miss" from a shot with 99% displayed accuracy. So the "improvement" you want is already there to some extent. [[User:Magic9mushroom|Magic9mushroom]] ([[User talk:Magic9mushroom|talk]]) 00:58, 2 September 2016 (UTC)

I fear that we disagree about the term ''dispersion cone''. I understand it as the normally distributed direction of the projectile, so that each shot is modeled by a single dispersion cone, which describes all the possible outcomes with their corresponding probabilities. This interpretation leaves no place for two dispersion cones. If UFO:EU chooses the wider or the narrower of some two dispersion cones depending on accuracy, then it largely defeats the cause of the normal model with respect to the non-linear dependency on distance, for the choice of either the ''hit'' or the ''miss'' dispersion cone is the definitive factor, whereas the subsequent modeling with the chosen cone is only secondary, because the ''hit'' cone almost always results in a hit and the ''miss'' one in a miss.

Is the algorithm that you have described documented anywhere? [[Accuracy_formula]] does not mention it and seems to imply a single dispersion cone per shot...[[User:Ant 222|Ant 222]] ([[User talk:Ant 222|talk]]) 17:08, 2 September 2016 (UTC)

=Data Analysis=

OK I did some quantitative analysis and the results are not good. The ''only'' weapons for which Aimed Fire has better efficiency of Accuracy::TU compared to Snap Fire, are Rockets and the Rocket Tank. In the notation above, there are only 3 weapons for which Kai > Ksn. In most cases, Snap fire is ''considerably'' more efficient - typically around 70% more efficient. Even for the Rocket weapons, Aimed Fire is only 25% (i.e. one-quarter) more effective. For all other weapons, including HWP and alien built-in attacks, snap fire is more efficient (in terms of generating hits on the target per unit of time). Obviously it is not good to have a game mechanic that is barely used because it has no real usefulness. I guess the proposal would be to raise the efficiency level of Aimed fire, and leave Snap fire where it is now. This would be the least unbalancing change, since Aimed fire is rarely used now, and even if it was more effective, it is tactically problematic to use because of the high TU cost. Even if you adjusted all weapons so that Aimed fire was 25% more efficient than Snap fire, I doubt that would be much incentive to use Aimed fire. 50% efficiency gain would be more likely to actually create real tactical alternatives that would get used by players in the game. By way of example, this would mean increasing the based Aimed accuracy of a Laser Rifle to around 200% (for 50% TU cost; vs Snap at 65% Accuracy for 25% TU cost). [[User:Spike|Spike]] 18:17, 6 December 2008 (CST)

:There's other measures of efficiency, as well. For example, with any explosive munition, Aimed fire gets a second chance because as a general rule, you don't want an explosive going off in the wrong place. Particularly true with the Large Rocket and HC-HE. (Also somewhat of an issue with the Small Launcher, but it's mitigated because affected units are only stunned, not killed.) On a similar note, aimed is nice in Scout-Sniper so you don't shoot the spotter(The aimed guy doesn't have to move much so has lots of TUs for aimed fire.) [[User:Arrow Quivershaft|Arrow Quivershaft]] 18:27, 6 December 2008 (CST)

:: Yes I definitely agree there are non-firepower benefits of Aimed fire, that are already present in the game. As you say these include control of collateral damage (with HE or with exposed scouts), and ammo-efficient (also "opportunity-efficient") use of single-shot weapons. Fair point! Can we list out all of the non-firepower benefits? I'm really trying hard to see if it's possible to make the case that Aimed fire is not pointless, from a game design / game balance point of view. [[User:Spike|Spike]] 19:21, 6 December 2008 (CST)

:Well, one big thing is that reloading a weapon takes 15 TUs flat. This is actually a fair bit. For a rookie, it can be anywhere from 1/4th to almost 1/3rd of his full TU allotment, whereas its just below 1/5th for a top-level veteran. Any weapon with a small clip is going to require reloading on a regular basis if repeated snap fire is used. Anything with a 1-round clip counts, any arguably, so does the Heavy Cannon. (Though the Blaster Launcher has no mode other than Aimed, so is only included for example). The more ammo you use, the more you need to carry, thus the more space you need in the transport.
:A single soldier can carry, at most, 5 rockets, 7 Blaster Bombs, 66 Heavy Cannon shots(11 clips), or 25 Small Launcher rounds. (These numbers do not take into account Strength limitations, or use of the Item Stacking bug. Also note that there's no reason you should need that many Small Launcher rounds.) Consider how many spaces this is on the transport, for one. Then multiply this across the number of associated weapons...you hit 80 pretty fast. Using lots of ammo means less room on the transport for other gear. Also consider how weighted down the soldier is. A soldier hauling around a rocket launcher and 4 reloads is carrying 50 units of weight, leaving not much room for other gear.
:The collateral damage is an issue that needs to be watched for, of course. Snap-firing a Large Rocket can kill large portions of your team if not done properly. Even if none of your soldiers are killed, you may destroy valuable equipment if not careful. (Especially true near UFO power sources!) And at range, snap fire's path can intersect the position of a soldier.
:Cost is yet another. In particular, in the case of the Small Launcher, ammunition requires Elerium to manufacture. And Large Rockets don't come too cheap if you're firing them off willy-nilly.
:And finally, when dealing with the tanks, the Ammo problem is even worse...you CAN'T reload in the middle of battle; you get one magazine and that's it. (This is only truly relevant for the Rocket Tank and Fusion Hovertank.) Plus ammo is even more expensive!
:There was another idea I had, but it escapes me currently. Still, I think this is a fairly comprehensive list. [[User:Arrow Quivershaft|Arrow Quivershaft]] 20:18, 6 December 2008 (CST)

=TU Efficiency Table=

The table below shows the extent to which Aimed fire is less efficient than Snap fire. A value of 50% would mean Aimed fire is half as efficient (in terms of accuracy:TU) as Snap fire. The table also shows what the required value of Aimed Accuracy % would need to be increased to, in order to make Aimed fire as efficient (100%) as Snap fire, or 125% as efficient, or 150% as efficient.

See also the [[Firepower Tables]] which show how ineffective Aimed fire is in terms of damage-on-target. The root cause of the damage-on-target inefficiency, is this TU inefficiency.

<table {{StdCenterTable}} class="sortable">
<caption><b>Aimed vs Snap fire - Accuracy::TU Efficiency<br>with corrective values for Aimed Accuracy
</b></caption>
<tr {{StdDescTable_Heading}}>
<th>Weapon</th><th>Aim Acc%</th><th>Aim:Snap</th><th>100%</th><th>125%</th><th>150%</th>
<tr><td>Pistol</td><td>78</td><td>78%</td><td>100</td><td>125</td><td>150</td></tr>
<tr><td>Rifle</td><td>110</td><td>57%</td><td>192</td><td>240</td><td>288</td></tr>
<tr><td>HC - AP</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>HC - HE</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>AC - AP</td><td>82</td><td>60%</td><td>136</td><td>170</td><td>204</td></tr>
<tr><td>AC - HE</td><td>82</td><td>60%</td><td>136</td><td>170</td><td>204</td></tr>
<tr><td>RocketSm</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>RocketLg</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>LaserP</td><td>68</td><td>62%</td><td>110</td><td>138</td><td>165</td></tr>
<tr><td>LaserR</td><td>100</td><td>77%</td><td>130</td><td>163</td><td>195</td></tr>
<tr><td>HvyLas</td><td>84</td><td>74%</td><td>114</td><td>142</td><td>170</td></tr>
<tr><td>HvyLas (XCU)</td><td>110</td><td>81%</td><td>136</td><td>170</td><td>205</td></tr>
<tr><td>PlasmaP</td><td>85</td><td>65%</td><td>130</td><td>163</td><td>195</td></tr>
<tr><td>PlasmaR</td><td>100</td><td>58%</td><td>172</td><td>215</td><td>258</td></tr>
<tr><td>HvyPlas</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Blast Bmb</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td></tr>
<tr><td>Stun Bmb</td><td>110</td><td>90%</td><td>122</td><td>152</td><td>183</td></tr>
<tr><td>Tk Cannon</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>Tk Rocket</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>Tk Laser</td><td>85</td><td>75%</td><td>114</td><td>142</td><td>170</td></tr>
<tr><td>Tk Plasma</td><td>100</td><td>59%</td><td>170</td><td>213</td><td>255</td></tr>
<tr><td>Tk Fusion</td><td>100</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td></tr>
<tr><td>Cyberdisc</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Celatid</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Sectopod</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>

</table>

=TU Efficiency Mods=

The following replacement OBDATA.DAT files implement the principle that Aimed fire should not be less efficient than Snap fire. To use these, make a safe copy of your original OBDATA.DAT in the GEODATA folder, then replace it with one of these files. You should see the new improved base accuracies (and in some cases reduced TU costs) in the in-game UFOPaedia.

* [[Media:OBDTU100.DAT]] fixes Aimed fire so it is exactly as efficient as Snap fire.
* [[Media:OBDTU125.DAT]] fixes Aimed fire so it is 125% more efficient then Snap fire. This is the same ratio between Snap and Aimed fire that exists for Rockets.
* [[Media:OBDTU150.DAT]] fixes Aimed fire so it is 150% more efficient then Snap fire. This is probably over-powerful, and too unbalancing in the other direction. Also, in some cases (Rifle and Plasma Rifle) it is necessary to reduce the TU cost of Aimed fire slightly, as otherwise Accuracy would need to be raised above 255% (not possible as it is held in a single unsigned byte).

[[Category:Enemy Unknown/UFO Defense]]

Accuracy vs TU Efficiency

2016-09-02T17:08:55Z

Ant 222: /* Discussion */ Added a comment

In almost every case (Rockets are the exception), Snap fire is a more efficient use of TUs than Aimed fire. This means Aimed fire is not useful apart from certain specialised activities.

=Proposal=

Would it be unreasonable to correct the TU and/or accuracy values of weapons, so that if we call the efficiency (hits per unit of time)

K = accuracy/TUs

and we have

Kai (K - Aimed)
Ksn (K - Snap)

we correct the game tables to ensure that for any given weapon:

Kai > Ksn

In English, we are saying that extra time spent on aiming is no less useful than time spent snap firing. Or, if I spend twice as long on an aimed shot than on a snap shot, my chance of hitting should be doubled.

( In an unmodified game, this relationship does not hold, for all cases except Rockets. )

The purpose of this modification would be to ensure that, in terms of delivering hits to the target per unit of time, Aimed fire is more effective than Snap fire, which in turn is more effective than Auto fire.

Otherwise there are few reasons not always use the fastest available fire rate.

(3 reasons I can think of are:

* Conserving ammo - often of minor importance, except with single launcher rounds (Rockets etc), especially rare/expensive ones such as Blaster Bombs.
* Avoiding "collateral damage" to friendly troops, civilians, or valuable recoverable items
* "First shot kill" - killing the target before it can reaction-fire

But for general combat, there is often no reason to prefer Aimed fire over Snap, or Snap over Auto.

=Discussion=

Analysis of 20th century battles showed that ordinary soldiers were more effective at killing the enemy when they were given automatic weapons. Resistance to equipping troops with full auto small arms as standard was mainly on ammunition cost grounds (as well as conservatism). This was further refined by studies showing that a burst mode (as used in XCom) was optimum.

However, this was true only for the ordinary troops, who were found to be too unsettled by combat to fire in a controlled fashion. For the minority who had the presence of mind to fire under control, taking slow, carefully aimed shots was more effective and this is where the bulk of the overall effective firepower of an entire formation would come from.

Now, which group do we think XCom soldiers fall into?

[[User:Spike|Spike]] 13:28, 10 November 2008 (CST)

:X-COM soldiers are selected as the best available volunteers from the various militaries of the funding nations, according to backstory. Thus they'd probably be more geared towards the latter class. However, given the...shall we say...less-than-ideal stats of some recruits, its clear that even then that's not going to hold. Bravery would probably be one of the main stats applicable to this argument. It should also be noted that X-COM soldiers are fighting a completely different war, one which could well make most regular soldiers break down from the stress alone. Think about it, for the first half of the game, at least, X-COM soldiers are out-equipped, fighting ALIENS, some 4 times thier own size, who can kill them in one glancing hit from a PLASMA weapon, while they themselves have trouble even hurting some of them, and whom are coming from OUTER SPACE in UFOs they can't scratch on the ground and which can VAPORIZE F-22s(or whatever the Interceptor is). That's not even mentioning the funding issues, terror attacks, or psychological scarring. And every time the Skyranger goes out, they can pretty much count on the fact that at least 2 or 3 of the people they're inside it with will be coming back to base in a body bag. This is liable to put ANYONE, even a battle-hardened combat vet of a normal earth military, off balance, at the very least. Which can be seen in how rapidly X-COM recruits tend to panic when things go bad. Overall troop morale would be one X-COM's (or any such organization's) greatest problems.

:As for the use of aiming/snap/auto, it's basically been established that in UFO, auto reigns supreme. Whereas in TFTD, auto fire is only available on a handful of weapons, with horrendous accuracy for it, and usually with a fairly small clip. I don't know how many Aquanauts I've had run dry on ammo at a critical moment because I used the Jet Harpoon's Autofire too liberally(read: use at all) TFTD's weapons, however, have awesome Aimed accuracy stats, swinging it in the opposite direction of UFO; aimed is the prefered fire of choice. Also, perhaps use Scout/Sniper some more if you want to use Aimed mode; it increases overall safety. :) [[User:Arrow Quivershaft|Arrow Quivershaft]] 13:50, 10 November 2008 (CST)

Good points there AQ. It's probably reasonable (for many reasons) to treat XCom's "elite" recruits as effectively rookies when tangling with aliens and alien weapons.

Thinking about auto modes, actually it does make sense that they have better firepower than the other modes. Otherwise why would they be used at all? Auto should be more effective per unit of time, less effective per unit of ammo - which it is.

That being the case, a more moderate proposal would be to tweak the game to ensure that Kai > Ksn, i.e. Aimed fire is more effective than Snap, per unit of time. Surely that is just common sense? Otherwise there is very little reason ever to Aim.

By the way, could you expand on your thoughts about Scout/Sniper? I'm not sure I understand how this tactic gives greater weight to Aimed Fire. Are there any considerations apart from reducing friendly fire and enemy reaction fire?

[[User:Spike|Spike]] 09:32, 11 November 2008 (CST)

: One additional benefit I can see for using the scout/sniper strategy other than the benefits already mentioned would be the fact that the sniper will not have to move as much, if at all. Therefore the sniper will have more TUs available to make aimed shots. Obviously this means nothing for some weapons that can only be fired once per turn on aimed, but for weapons that can be aimed several times, then every extra TU helps. Just as snaps and auto shots bank on extra attempts to improve their odds of success, the same can apply to aimed shots too. -[[User:NKF|NKF]] 22:38, 12 November 2008 (CST)

In real combat, both quick and carefully aimed shots are useful depending on the situation, for at least two reasons. In situations such as an ambush, when the target is unaware of the firer, it is beneficial to hit it with the first shot, regardless or how long it may take to aim precisely, because after that the firer's position, if only approximately, will be made known to the enemy, who will then be prepared for fire from the same quarter and will seek cover and possibly fire back. This consideration can hardly be accounted for in the classic X-COM (but must be in the games it inspired).

The second reason is that snap shots are more effective at close range and aimed ones at long range. It happens because at short range the dispersion cone is much smaller than the target's angular area and aiming consists of pointing the weapon roughly at the target without the use of sights. The hit change is near 100% so the one who shorts first is the winner. At long range, however, the situation is reversed. The weapon must be aligned carefully to point at the small target and stabilized to narrow down the dispersion cone. The effect of distance is not uniform across all ranges but follows the behavior of the quantiles of the normal distribution:

[[File:HitChance1d.png|||center|||||One-dimensinal formula for hit chance]]

where Φ is the [https://en.wikipedia.org/wiki/Normal_distribution#Cumulative_distribution_function cumulative normal distribution function], ''d'' the distance to the target, and ''r'' the target's characteristic radius as projected in the firer's direction. The standard deviation σ determines the opening angle of the dispersion cone and thus the accuracy of the shot.
Here are the graphs for three different accuracies:

[[File:HitChanceVsDistance.png|center|Hit chance vs. distance]]

Precise aiming takes a certain time determined by the weapon and the firer, after which accuracy reaches a plateau and then starts to degrade due to fatigue. During the effective aiming stage the rate of accuracy increase is highest at the beginning and becomes lower at it approaches the plateau, but in the end the probability of defeating a remote target is improved out of all proportion with regard to the time spent aiming.

That being said, I don't think serious improvement is possible unless someone can change the hit-chance formula so that it will approximate, if loosely, the varying effect of distance at different ranges described above. As distance increases the effectiveness of auto- and snap shots should become lower compared to that of an aimed shot. [[User:Ant 222|Ant 222]] ([[User talk:Ant 222|talk]]) 15:28, 1 September 2016 (UTC)

:UFO:EU does actually use dispersion cones, FYI. The displayed accuracy of the shot is the chance that it will use the narrower "hit" dispersion cone instead of the wider "miss" dispersion cone, but "hits" can miss (usually due to cover, such as trying to hit an alien in a building through a window, but at long ranges true misses are possible against small targets) and "misses" can hit (most obviously at point-blank range). The size of the cones is also adjusted based on that accuracy, so the dispersion of a "miss" from a shot with 10% displayed accuracy is much larger than that of a "miss" from a shot with 99% displayed accuracy. So the "improvement" you want is already there to some extent. [[User:Magic9mushroom|Magic9mushroom]] ([[User talk:Magic9mushroom|talk]]) 00:58, 2 September 2016 (UTC)

I fear that we disagree about the term ''dispersion cone''. I understand it as the normally distributed direction of the projectile, so that each shot is modeled by a single dispersion cone, which describes all the possible outcomes with their corresponding probabilities. This interpretation leaves no place for two dispersion cones. If UFO:EU chooses the wider or the narrower of some two dispersion cones depending on accuracy, then it largely defeats the cause of the normal model with respect to the non-linear dependency on distance, for the choice of either the ''hit'' or the ''miss'' dispersion cone is the definitive factor, whereas the subsequent modeling with the chosen cone is only secondary, because the ''hit'' cone almost always results in a hit and the ''miss'' one in a miss.

Is the algorithm that you have described documented somewhere? [[Accuracy_formula]] does not mention it and seems to imply a single dispersion cone per shot...[[User:Ant 222|Ant 222]] ([[User talk:Ant 222|talk]]) 17:08, 2 September 2016 (UTC)

=Data Analysis=

OK I did some quantitative analysis and the results are not good. The ''only'' weapons for which Aimed Fire has better efficiency of Accuracy::TU compared to Snap Fire, are Rockets and the Rocket Tank. In the notation above, there are only 3 weapons for which Kai > Ksn. In most cases, Snap fire is ''considerably'' more efficient - typically around 70% more efficient. Even for the Rocket weapons, Aimed Fire is only 25% (i.e. one-quarter) more effective. For all other weapons, including HWP and alien built-in attacks, snap fire is more efficient (in terms of generating hits on the target per unit of time). Obviously it is not good to have a game mechanic that is barely used because it has no real usefulness. I guess the proposal would be to raise the efficiency level of Aimed fire, and leave Snap fire where it is now. This would be the least unbalancing change, since Aimed fire is rarely used now, and even if it was more effective, it is tactically problematic to use because of the high TU cost. Even if you adjusted all weapons so that Aimed fire was 25% more efficient than Snap fire, I doubt that would be much incentive to use Aimed fire. 50% efficiency gain would be more likely to actually create real tactical alternatives that would get used by players in the game. By way of example, this would mean increasing the based Aimed accuracy of a Laser Rifle to around 200% (for 50% TU cost; vs Snap at 65% Accuracy for 25% TU cost). [[User:Spike|Spike]] 18:17, 6 December 2008 (CST)

:There's other measures of efficiency, as well. For example, with any explosive munition, Aimed fire gets a second chance because as a general rule, you don't want an explosive going off in the wrong place. Particularly true with the Large Rocket and HC-HE. (Also somewhat of an issue with the Small Launcher, but it's mitigated because affected units are only stunned, not killed.) On a similar note, aimed is nice in Scout-Sniper so you don't shoot the spotter(The aimed guy doesn't have to move much so has lots of TUs for aimed fire.) [[User:Arrow Quivershaft|Arrow Quivershaft]] 18:27, 6 December 2008 (CST)

:: Yes I definitely agree there are non-firepower benefits of Aimed fire, that are already present in the game. As you say these include control of collateral damage (with HE or with exposed scouts), and ammo-efficient (also "opportunity-efficient") use of single-shot weapons. Fair point! Can we list out all of the non-firepower benefits? I'm really trying hard to see if it's possible to make the case that Aimed fire is not pointless, from a game design / game balance point of view. [[User:Spike|Spike]] 19:21, 6 December 2008 (CST)

:Well, one big thing is that reloading a weapon takes 15 TUs flat. This is actually a fair bit. For a rookie, it can be anywhere from 1/4th to almost 1/3rd of his full TU allotment, whereas its just below 1/5th for a top-level veteran. Any weapon with a small clip is going to require reloading on a regular basis if repeated snap fire is used. Anything with a 1-round clip counts, any arguably, so does the Heavy Cannon. (Though the Blaster Launcher has no mode other than Aimed, so is only included for example). The more ammo you use, the more you need to carry, thus the more space you need in the transport.
:A single soldier can carry, at most, 5 rockets, 7 Blaster Bombs, 66 Heavy Cannon shots(11 clips), or 25 Small Launcher rounds. (These numbers do not take into account Strength limitations, or use of the Item Stacking bug. Also note that there's no reason you should need that many Small Launcher rounds.) Consider how many spaces this is on the transport, for one. Then multiply this across the number of associated weapons...you hit 80 pretty fast. Using lots of ammo means less room on the transport for other gear. Also consider how weighted down the soldier is. A soldier hauling around a rocket launcher and 4 reloads is carrying 50 units of weight, leaving not much room for other gear.
:The collateral damage is an issue that needs to be watched for, of course. Snap-firing a Large Rocket can kill large portions of your team if not done properly. Even if none of your soldiers are killed, you may destroy valuable equipment if not careful. (Especially true near UFO power sources!) And at range, snap fire's path can intersect the position of a soldier.
:Cost is yet another. In particular, in the case of the Small Launcher, ammunition requires Elerium to manufacture. And Large Rockets don't come too cheap if you're firing them off willy-nilly.
:And finally, when dealing with the tanks, the Ammo problem is even worse...you CAN'T reload in the middle of battle; you get one magazine and that's it. (This is only truly relevant for the Rocket Tank and Fusion Hovertank.) Plus ammo is even more expensive!
:There was another idea I had, but it escapes me currently. Still, I think this is a fairly comprehensive list. [[User:Arrow Quivershaft|Arrow Quivershaft]] 20:18, 6 December 2008 (CST)

=TU Efficiency Table=

The table below shows the extent to which Aimed fire is less efficient than Snap fire. A value of 50% would mean Aimed fire is half as efficient (in terms of accuracy:TU) as Snap fire. The table also shows what the required value of Aimed Accuracy % would need to be increased to, in order to make Aimed fire as efficient (100%) as Snap fire, or 125% as efficient, or 150% as efficient.

See also the [[Firepower Tables]] which show how ineffective Aimed fire is in terms of damage-on-target. The root cause of the damage-on-target inefficiency, is this TU inefficiency.

<table {{StdCenterTable}} class="sortable">
<caption><b>Aimed vs Snap fire - Accuracy::TU Efficiency<br>with corrective values for Aimed Accuracy
</b></caption>
<tr {{StdDescTable_Heading}}>
<th>Weapon</th><th>Aim Acc%</th><th>Aim:Snap</th><th>100%</th><th>125%</th><th>150%</th>
<tr><td>Pistol</td><td>78</td><td>78%</td><td>100</td><td>125</td><td>150</td></tr>
<tr><td>Rifle</td><td>110</td><td>57%</td><td>192</td><td>240</td><td>288</td></tr>
<tr><td>HC - AP</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>HC - HE</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>AC - AP</td><td>82</td><td>60%</td><td>136</td><td>170</td><td>204</td></tr>
<tr><td>AC - HE</td><td>82</td><td>60%</td><td>136</td><td>170</td><td>204</td></tr>
<tr><td>RocketSm</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>RocketLg</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>LaserP</td><td>68</td><td>62%</td><td>110</td><td>138</td><td>165</td></tr>
<tr><td>LaserR</td><td>100</td><td>77%</td><td>130</td><td>163</td><td>195</td></tr>
<tr><td>HvyLas</td><td>84</td><td>74%</td><td>114</td><td>142</td><td>170</td></tr>
<tr><td>HvyLas (XCU)</td><td>110</td><td>81%</td><td>136</td><td>170</td><td>205</td></tr>
<tr><td>PlasmaP</td><td>85</td><td>65%</td><td>130</td><td>163</td><td>195</td></tr>
<tr><td>PlasmaR</td><td>100</td><td>58%</td><td>172</td><td>215</td><td>258</td></tr>
<tr><td>HvyPlas</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Blast Bmb</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td></tr>
<tr><td>Stun Bmb</td><td>110</td><td>90%</td><td>122</td><td>152</td><td>183</td></tr>
<tr><td>Tk Cannon</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>Tk Rocket</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>Tk Laser</td><td>85</td><td>75%</td><td>114</td><td>142</td><td>170</td></tr>
<tr><td>Tk Plasma</td><td>100</td><td>59%</td><td>170</td><td>213</td><td>255</td></tr>
<tr><td>Tk Fusion</td><td>100</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td></tr>
<tr><td>Cyberdisc</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Celatid</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Sectopod</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>

</table>

=TU Efficiency Mods=

The following replacement OBDATA.DAT files implement the principle that Aimed fire should not be less efficient than Snap fire. To use these, make a safe copy of your original OBDATA.DAT in the GEODATA folder, then replace it with one of these files. You should see the new improved base accuracies (and in some cases reduced TU costs) in the in-game UFOPaedia.

* [[Media:OBDTU100.DAT]] fixes Aimed fire so it is exactly as efficient as Snap fire.
* [[Media:OBDTU125.DAT]] fixes Aimed fire so it is 125% more efficient then Snap fire. This is the same ratio between Snap and Aimed fire that exists for Rockets.
* [[Media:OBDTU150.DAT]] fixes Aimed fire so it is 150% more efficient then Snap fire. This is probably over-powerful, and too unbalancing in the other direction. Also, in some cases (Rifle and Plasma Rifle) it is necessary to reduce the TU cost of Aimed fire slightly, as otherwise Accuracy would need to be raised above 255% (not possible as it is held in a single unsigned byte).

[[Category:Enemy Unknown/UFO Defense]]

Guidelines to writing articles

2016-09-01T15:49:54Z

Ant 222: Grammar correction

Here are a few tips to writing articles on the X-COM Wiki:

==General Rules==

* You need to log on to your account before posting or editing new articles here as we had to put certain measures in place to reduce spammers.

* For consistency the proper way to refer to X-COM is '''X-COM'''. The original unhyphenated variant '''XCOM''' can be used for articles concerning [[Enemy Unknown (2012)]] and [[The Bureau: XCOM Declassified]] and future games where applicable.

* Remember, these are only tips and guidelines. If you have a good reason to break any for your article, do so.

==Creating New Pages==
* If you are unsure about creating any new articles, or are having second thoughts about the content, discuss it with other article writers before proceeding. Do this through whatever channels are available to you. The "discussion" (or "talk") pages of articles is a good place for this; [[Talk:Main Page]] is where site-wide editing issues are discussed. Users' individual Talk pages are also a good place to conduct editing discussions.

* When naming a new page add a (game) suffix to the page name in case the same term appears in more than one game in the series. Some examples of how to name pages would be: [[Medi-Kit (EU)]], [[Research (TFTD)]] or [[Battlescape Overview (Apocalypse)]]. In cases of specific game names like [[Snakeman]], [[Lobsterman]] or [[Megapol]] avoid using suffixes for easiness of linking.

==Writing Style & Page Content==

* When writing articles try to keep a '''Neutral Point Of View''' (NPOV) regarding its content and avoid personal references. And remember that any content you enter can and will be discussed, edited or changed.

* '''Don't fret too much when deciding between American and British spelling variations of the same English words'''. It does not matter. Use whatever convention is comfortable and avoid editing wars by asking for spelling confirmation from the author. The best way to avoid a spelling dispute is to refer to its in-game usage.

* Use capital letters when needed.

* Punctuation. Good punctuation clarifies and eliminates potential confusion.

* Use ellipses (...) as a last resort and only if it cannot be avoided.

* Do not write as if you were in a chat room or text messaging. Write out your words and use complete sentences.

* Avoid emoticons.

* Always double-check your spelling, punctuation and grammar before submitting new articles or any major edits. This helps reduce future editing work. When submitting changes to an article (no matter how minor), first preview it, then save it. Previewing catches lots of common errors (like broken/wrong wikilinks).

* Use section headings to divide your articles into manageable segments.

* When submitting in-game images from any games in the X-COM series, kindly convert it to .PNG ('''P'''ortable '''N'''etwork '''G'''raphics) format. GIF's are also tolerable, but avoid JPEG's at all costs since it is a lossy image format that is suitable for photo-realistic images, but works very poorly with images with limited palettes such as used in the first three X-COM games.
:*For PNGs, remember that the color depth of the image greatly influences the size of the image. Set to 16 million colours, the file size can be depressingly large. Where possible, game images saved as PNG should have the color depth set to 256 color (or lesser) to keep the size small.
:*Consider also using a PNG optimizer such as [http://advsys.net/ken/utils.htm PNGOUT] to reduce the size even further. There may also be other optimizers out there.

==Linking Pages==
* Make wikilinks to the names of aliens, equipment, etc. ''Don't repeat wikilinks'' within an article: turn the first reference into a wikilink, but leave the remaining references as "plain" text.

* If you link to existing articles, but they appear red (page does not exist), check to see if you are using the same spelling and capitalization.

* If your article contains too many links to the same articles, consider revising it and using a ''See Also...'' section at the end of the article.

==Categorizing Pages==

* Categorize articles. A list of existing categories can be seen at [[Special:Categories]].

* If there isn't a category to fit your page you can easily create one by adding the <nowiki>[[Category:NAMEHERE]]</nowiki> at the bottom of your page. If the pages belonging to that category belong to a specific game add a game suffix to the name, such as <nowiki>[[Category: Alien Life Forms (EU)]], [[Category: Alien Life Forms (TFTD)]] or [[Category: Alien Life Forms (Apocalypse)]]</nowiki>

* When adding non-canon material that is not in the games but that you've created yourself (such as fanfiction) please add the <nowiki>[[Category:Fiction]]</nowiki> tag at the end of the text.

==Talk Pages==

* Try not to use the main articles as a chat page. Use the talk page of that page to do so.

* Do sign your messages in Talk pages. Use four tildes <nowiki>~~~~</nowiki> to insert your username and a timestamp. Alternately, the second to last button in the edit box will insert this for you at the cursor.

==See Also==
* [[UFOpaedia:Community_Portal|Community Portal]]

Accuracy vs TU Efficiency

2016-09-01T15:28:13Z

Ant 222: Added the attribution

In almost every case (Rockets are the exception), Snap fire is a more efficient use of TUs than Aimed fire. This means Aimed fire is not useful apart from certain specialised activities.

=Proposal=

Would it be unreasonable to correct the TU and/or accuracy values of weapons, so that if we call the efficiency (hits per unit of time)

K = accuracy/TUs

and we have

Kai (K - Aimed)
Ksn (K - Snap)

we correct the game tables to ensure that for any given weapon:

Kai > Ksn

In English, we are saying that extra time spent on aiming is no less useful than time spent snap firing. Or, if I spend twice as long on an aimed shot than on a snap shot, my chance of hitting should be doubled.

( In an unmodified game, this relationship does not hold, for all cases except Rockets. )

The purpose of this modification would be to ensure that, in terms of delivering hits to the target per unit of time, Aimed fire is more effective than Snap fire, which in turn is more effective than Auto fire.

Otherwise there are few reasons not always use the fastest available fire rate.

(3 reasons I can think of are:

* Conserving ammo - often of minor importance, except with single launcher rounds (Rockets etc), especially rare/expensive ones such as Blaster Bombs.
* Avoiding "collateral damage" to friendly troops, civilians, or valuable recoverable items
* "First shot kill" - killing the target before it can reaction-fire

But for general combat, there is often no reason to prefer Aimed fire over Snap, or Snap over Auto.

=Discussion=

Analysis of 20th century battles showed that ordinary soldiers were more effective at killing the enemy when they were given automatic weapons. Resistance to equipping troops with full auto small arms as standard was mainly on ammunition cost grounds (as well as conservatism). This was further refined by studies showing that a burst mode (as used in XCom) was optimum.

However, this was true only for the ordinary troops, who were found to be too unsettled by combat to fire in a controlled fashion. For the minority who had the presence of mind to fire under control, taking slow, carefully aimed shots was more effective and this is where the bulk of the overall effective firepower of an entire formation would come from.

Now, which group do we think XCom soldiers fall into?

[[User:Spike|Spike]] 13:28, 10 November 2008 (CST)

:X-COM soldiers are selected as the best available volunteers from the various militaries of the funding nations, according to backstory. Thus they'd probably be more geared towards the latter class. However, given the...shall we say...less-than-ideal stats of some recruits, its clear that even then that's not going to hold. Bravery would probably be one of the main stats applicable to this argument. It should also be noted that X-COM soldiers are fighting a completely different war, one which could well make most regular soldiers break down from the stress alone. Think about it, for the first half of the game, at least, X-COM soldiers are out-equipped, fighting ALIENS, some 4 times thier own size, who can kill them in one glancing hit from a PLASMA weapon, while they themselves have trouble even hurting some of them, and whom are coming from OUTER SPACE in UFOs they can't scratch on the ground and which can VAPORIZE F-22s(or whatever the Interceptor is). That's not even mentioning the funding issues, terror attacks, or psychological scarring. And every time the Skyranger goes out, they can pretty much count on the fact that at least 2 or 3 of the people they're inside it with will be coming back to base in a body bag. This is liable to put ANYONE, even a battle-hardened combat vet of a normal earth military, off balance, at the very least. Which can be seen in how rapidly X-COM recruits tend to panic when things go bad. Overall troop morale would be one X-COM's (or any such organization's) greatest problems.

:As for the use of aiming/snap/auto, it's basically been established that in UFO, auto reigns supreme. Whereas in TFTD, auto fire is only available on a handful of weapons, with horrendous accuracy for it, and usually with a fairly small clip. I don't know how many Aquanauts I've had run dry on ammo at a critical moment because I used the Jet Harpoon's Autofire too liberally(read: use at all) TFTD's weapons, however, have awesome Aimed accuracy stats, swinging it in the opposite direction of UFO; aimed is the prefered fire of choice. Also, perhaps use Scout/Sniper some more if you want to use Aimed mode; it increases overall safety. :) [[User:Arrow Quivershaft|Arrow Quivershaft]] 13:50, 10 November 2008 (CST)

Good points there AQ. It's probably reasonable (for many reasons) to treat XCom's "elite" recruits as effectively rookies when tangling with aliens and alien weapons.

Thinking about auto modes, actually it does make sense that they have better firepower than the other modes. Otherwise why would they be used at all? Auto should be more effective per unit of time, less effective per unit of ammo - which it is.

That being the case, a more moderate proposal would be to tweak the game to ensure that Kai > Ksn, i.e. Aimed fire is more effective than Snap, per unit of time. Surely that is just common sense? Otherwise there is very little reason ever to Aim.

By the way, could you expand on your thoughts about Scout/Sniper? I'm not sure I understand how this tactic gives greater weight to Aimed Fire. Are there any considerations apart from reducing friendly fire and enemy reaction fire?

[[User:Spike|Spike]] 09:32, 11 November 2008 (CST)

: One additional benefit I can see for using the scout/sniper strategy other than the benefits already mentioned would be the fact that the sniper will not have to move as much, if at all. Therefore the sniper will have more TUs available to make aimed shots. Obviously this means nothing for some weapons that can only be fired once per turn on aimed, but for weapons that can be aimed several times, then every extra TU helps. Just as snaps and auto shots bank on extra attempts to improve their odds of success, the same can apply to aimed shots too. -[[User:NKF|NKF]] 22:38, 12 November 2008 (CST)

In real combat, both quick and carefully aimed shots are useful depending on the situation, for at least two reasons. In situations such as an ambush, when the target is unaware of the firer, it is beneficial to hit it with the first shot, regardless or how long it may take to aim precisely, because after that the firer's position, if only approximately, will be made known to the enemy, who will then be prepared for fire from the same quarter and will seek cover and possibly fire back. This consideration can hardly be accounted for in the classic X-COM (but must be in the games it inspired).

The second reason is that snap shots are more effective at close range and aimed ones at long range. It happens because at short range the dispersion cone is much smaller than the target's angular area and aiming consists of pointing the weapon roughly at the target without the use of sights. The hit change is near 100% so the one who shorts first is the winner. At long range, however, the situation is reversed. The weapon must be aligned carefully to point at the small target and stabilized to narrow down the dispersion cone. The effect of distance is not uniform across all ranges but follows the behavior of the quantiles of the normal distribution:

[[File:HitChance1d.png|||center|||||One-dimensinal formula for hit chance]]

where Φ is the [https://en.wikipedia.org/wiki/Normal_distribution#Cumulative_distribution_function cumulative normal distribution function], ''d'' the distance to the target, and ''r'' the target's characteristic radius as projected in the firer's direction. The standard deviation σ determines the opening angle of the dispersion cone and thus the accuracy of the shot.
Here are the graphs for three different accuracies:

[[File:HitChanceVsDistance.png|center|Hit chance vs. distance]]

Precise aiming takes a certain time determined by the weapon and the firer, after which accuracy reaches a plateau and then starts to degrade due to fatigue. During the effective aiming stage the rate of accuracy increase is highest at the beginning and becomes lower at it approaches the plateau, but in the end the probability of defeating a remote target is improved out of all proportion with regard to the time spent aiming.

That being said, I don't think serious improvement is possible unless someone can change the hit-chance formula so that it will approximate, if loosely, the varying effect of distance at different ranges described above. As distance increases the effectiveness of auto- and snap shots should become lower compared to that of an aimed shot. [[User:Ant 222|Ant 222]] ([[User talk:Ant 222|talk]]) 15:28, 1 September 2016 (UTC)

=Data Analysis=

OK I did some quantitative analysis and the results are not good. The ''only'' weapons for which Aimed Fire has better efficiency of Accuracy::TU compared to Snap Fire, are Rockets and the Rocket Tank. In the notation above, there are only 3 weapons for which Kai > Ksn. In most cases, Snap fire is ''considerably'' more efficient - typically around 70% more efficient. Even for the Rocket weapons, Aimed Fire is only 25% (i.e. one-quarter) more effective. For all other weapons, including HWP and alien built-in attacks, snap fire is more efficient (in terms of generating hits on the target per unit of time). Obviously it is not good to have a game mechanic that is barely used because it has no real usefulness. I guess the proposal would be to raise the efficiency level of Aimed fire, and leave Snap fire where it is now. This would be the least unbalancing change, since Aimed fire is rarely used now, and even if it was more effective, it is tactically problematic to use because of the high TU cost. Even if you adjusted all weapons so that Aimed fire was 25% more efficient than Snap fire, I doubt that would be much incentive to use Aimed fire. 50% efficiency gain would be more likely to actually create real tactical alternatives that would get used by players in the game. By way of example, this would mean increasing the based Aimed accuracy of a Laser Rifle to around 200% (for 50% TU cost; vs Snap at 65% Accuracy for 25% TU cost). [[User:Spike|Spike]] 18:17, 6 December 2008 (CST)

:There's other measures of efficiency, as well. For example, with any explosive munition, Aimed fire gets a second chance because as a general rule, you don't want an explosive going off in the wrong place. Particularly true with the Large Rocket and HC-HE. (Also somewhat of an issue with the Small Launcher, but it's mitigated because affected units are only stunned, not killed.) On a similar note, aimed is nice in Scout-Sniper so you don't shoot the spotter(The aimed guy doesn't have to move much so has lots of TUs for aimed fire.) [[User:Arrow Quivershaft|Arrow Quivershaft]] 18:27, 6 December 2008 (CST)

:: Yes I definitely agree there are non-firepower benefits of Aimed fire, that are already present in the game. As you say these include control of collateral damage (with HE or with exposed scouts), and ammo-efficient (also "opportunity-efficient") use of single-shot weapons. Fair point! Can we list out all of the non-firepower benefits? I'm really trying hard to see if it's possible to make the case that Aimed fire is not pointless, from a game design / game balance point of view. [[User:Spike|Spike]] 19:21, 6 December 2008 (CST)

:Well, one big thing is that reloading a weapon takes 15 TUs flat. This is actually a fair bit. For a rookie, it can be anywhere from 1/4th to almost 1/3rd of his full TU allotment, whereas its just below 1/5th for a top-level veteran. Any weapon with a small clip is going to require reloading on a regular basis if repeated snap fire is used. Anything with a 1-round clip counts, any arguably, so does the Heavy Cannon. (Though the Blaster Launcher has no mode other than Aimed, so is only included for example). The more ammo you use, the more you need to carry, thus the more space you need in the transport.
:A single soldier can carry, at most, 5 rockets, 7 Blaster Bombs, 66 Heavy Cannon shots(11 clips), or 25 Small Launcher rounds. (These numbers do not take into account Strength limitations, or use of the Item Stacking bug. Also note that there's no reason you should need that many Small Launcher rounds.) Consider how many spaces this is on the transport, for one. Then multiply this across the number of associated weapons...you hit 80 pretty fast. Using lots of ammo means less room on the transport for other gear. Also consider how weighted down the soldier is. A soldier hauling around a rocket launcher and 4 reloads is carrying 50 units of weight, leaving not much room for other gear.
:The collateral damage is an issue that needs to be watched for, of course. Snap-firing a Large Rocket can kill large portions of your team if not done properly. Even if none of your soldiers are killed, you may destroy valuable equipment if not careful. (Especially true near UFO power sources!) And at range, snap fire's path can intersect the position of a soldier.
:Cost is yet another. In particular, in the case of the Small Launcher, ammunition requires Elerium to manufacture. And Large Rockets don't come too cheap if you're firing them off willy-nilly.
:And finally, when dealing with the tanks, the Ammo problem is even worse...you CAN'T reload in the middle of battle; you get one magazine and that's it. (This is only truly relevant for the Rocket Tank and Fusion Hovertank.) Plus ammo is even more expensive!
:There was another idea I had, but it escapes me currently. Still, I think this is a fairly comprehensive list. [[User:Arrow Quivershaft|Arrow Quivershaft]] 20:18, 6 December 2008 (CST)

=TU Efficiency Table=

The table below shows the extent to which Aimed fire is less efficient than Snap fire. A value of 50% would mean Aimed fire is half as efficient (in terms of accuracy:TU) as Snap fire. The table also shows what the required value of Aimed Accuracy % would need to be increased to, in order to make Aimed fire as efficient (100%) as Snap fire, or 125% as efficient, or 150% as efficient.

See also the [[Firepower Tables]] which show how ineffective Aimed fire is in terms of damage-on-target. The root cause of the damage-on-target inefficiency, is this TU inefficiency.

<table {{StdCenterTable}} class="sortable">
<caption><b>Aimed vs Snap fire - Accuracy::TU Efficiency<br>with corrective values for Aimed Accuracy
</b></caption>
<tr {{StdDescTable_Heading}}>
<th>Weapon</th><th>Aim Acc%</th><th>Aim:Snap</th><th>100%</th><th>125%</th><th>150%</th>
<tr><td>Pistol</td><td>78</td><td>78%</td><td>100</td><td>125</td><td>150</td></tr>
<tr><td>Rifle</td><td>110</td><td>57%</td><td>192</td><td>240</td><td>288</td></tr>
<tr><td>HC - AP</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>HC - HE</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>AC - AP</td><td>82</td><td>60%</td><td>136</td><td>170</td><td>204</td></tr>
<tr><td>AC - HE</td><td>82</td><td>60%</td><td>136</td><td>170</td><td>204</td></tr>
<tr><td>RocketSm</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>RocketLg</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>LaserP</td><td>68</td><td>62%</td><td>110</td><td>138</td><td>165</td></tr>
<tr><td>LaserR</td><td>100</td><td>77%</td><td>130</td><td>163</td><td>195</td></tr>
<tr><td>HvyLas</td><td>84</td><td>74%</td><td>114</td><td>142</td><td>170</td></tr>
<tr><td>HvyLas (XCU)</td><td>110</td><td>81%</td><td>136</td><td>170</td><td>205</td></tr>
<tr><td>PlasmaP</td><td>85</td><td>65%</td><td>130</td><td>163</td><td>195</td></tr>
<tr><td>PlasmaR</td><td>100</td><td>58%</td><td>172</td><td>215</td><td>258</td></tr>
<tr><td>HvyPlas</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Blast Bmb</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td></tr>
<tr><td>Stun Bmb</td><td>110</td><td>90%</td><td>122</td><td>152</td><td>183</td></tr>
<tr><td>Tk Cannon</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>Tk Rocket</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>Tk Laser</td><td>85</td><td>75%</td><td>114</td><td>142</td><td>170</td></tr>
<tr><td>Tk Plasma</td><td>100</td><td>59%</td><td>170</td><td>213</td><td>255</td></tr>
<tr><td>Tk Fusion</td><td>100</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td></tr>
<tr><td>Cyberdisc</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Celatid</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Sectopod</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>

</table>

=TU Efficiency Mods=

The following replacement OBDATA.DAT files implement the principle that Aimed fire should not be less efficient than Snap fire. To use these, make a safe copy of your original OBDATA.DAT in the GEODATA folder, then replace it with one of these files. You should see the new improved base accuracies (and in some cases reduced TU costs) in the in-game UFOPaedia.

* [[Media:OBDTU100.DAT]] fixes Aimed fire so it is exactly as efficient as Snap fire.
* [[Media:OBDTU125.DAT]] fixes Aimed fire so it is 125% more efficient then Snap fire. This is the same ratio between Snap and Aimed fire that exists for Rockets.
* [[Media:OBDTU150.DAT]] fixes Aimed fire so it is 150% more efficient then Snap fire. This is probably over-powerful, and too unbalancing in the other direction. Also, in some cases (Rifle and Plasma Rifle) it is necessary to reduce the TU cost of Aimed fire slightly, as otherwise Accuracy would need to be raised above 255% (not possible as it is held in a single unsigned byte).

[[Category:Enemy Unknown/UFO Defense]]

Accuracy vs TU Efficiency

2016-09-01T15:27:33Z

Ant 222: Edited my comment in the Discussion section

In almost every case (Rockets are the exception), Snap fire is a more efficient use of TUs than Aimed fire. This means Aimed fire is not useful apart from certain specialised activities.

=Proposal=

Would it be unreasonable to correct the TU and/or accuracy values of weapons, so that if we call the efficiency (hits per unit of time)

K = accuracy/TUs

and we have

Kai (K - Aimed)
Ksn (K - Snap)

we correct the game tables to ensure that for any given weapon:

Kai > Ksn

In English, we are saying that extra time spent on aiming is no less useful than time spent snap firing. Or, if I spend twice as long on an aimed shot than on a snap shot, my chance of hitting should be doubled.

( In an unmodified game, this relationship does not hold, for all cases except Rockets. )

The purpose of this modification would be to ensure that, in terms of delivering hits to the target per unit of time, Aimed fire is more effective than Snap fire, which in turn is more effective than Auto fire.

Otherwise there are few reasons not always use the fastest available fire rate.

(3 reasons I can think of are:

* Conserving ammo - often of minor importance, except with single launcher rounds (Rockets etc), especially rare/expensive ones such as Blaster Bombs.
* Avoiding "collateral damage" to friendly troops, civilians, or valuable recoverable items
* "First shot kill" - killing the target before it can reaction-fire

But for general combat, there is often no reason to prefer Aimed fire over Snap, or Snap over Auto.

=Discussion=

Analysis of 20th century battles showed that ordinary soldiers were more effective at killing the enemy when they were given automatic weapons. Resistance to equipping troops with full auto small arms as standard was mainly on ammunition cost grounds (as well as conservatism). This was further refined by studies showing that a burst mode (as used in XCom) was optimum.

However, this was true only for the ordinary troops, who were found to be too unsettled by combat to fire in a controlled fashion. For the minority who had the presence of mind to fire under control, taking slow, carefully aimed shots was more effective and this is where the bulk of the overall effective firepower of an entire formation would come from.

Now, which group do we think XCom soldiers fall into?

[[User:Spike|Spike]] 13:28, 10 November 2008 (CST)

:X-COM soldiers are selected as the best available volunteers from the various militaries of the funding nations, according to backstory. Thus they'd probably be more geared towards the latter class. However, given the...shall we say...less-than-ideal stats of some recruits, its clear that even then that's not going to hold. Bravery would probably be one of the main stats applicable to this argument. It should also be noted that X-COM soldiers are fighting a completely different war, one which could well make most regular soldiers break down from the stress alone. Think about it, for the first half of the game, at least, X-COM soldiers are out-equipped, fighting ALIENS, some 4 times thier own size, who can kill them in one glancing hit from a PLASMA weapon, while they themselves have trouble even hurting some of them, and whom are coming from OUTER SPACE in UFOs they can't scratch on the ground and which can VAPORIZE F-22s(or whatever the Interceptor is). That's not even mentioning the funding issues, terror attacks, or psychological scarring. And every time the Skyranger goes out, they can pretty much count on the fact that at least 2 or 3 of the people they're inside it with will be coming back to base in a body bag. This is liable to put ANYONE, even a battle-hardened combat vet of a normal earth military, off balance, at the very least. Which can be seen in how rapidly X-COM recruits tend to panic when things go bad. Overall troop morale would be one X-COM's (or any such organization's) greatest problems.

:As for the use of aiming/snap/auto, it's basically been established that in UFO, auto reigns supreme. Whereas in TFTD, auto fire is only available on a handful of weapons, with horrendous accuracy for it, and usually with a fairly small clip. I don't know how many Aquanauts I've had run dry on ammo at a critical moment because I used the Jet Harpoon's Autofire too liberally(read: use at all) TFTD's weapons, however, have awesome Aimed accuracy stats, swinging it in the opposite direction of UFO; aimed is the prefered fire of choice. Also, perhaps use Scout/Sniper some more if you want to use Aimed mode; it increases overall safety. :) [[User:Arrow Quivershaft|Arrow Quivershaft]] 13:50, 10 November 2008 (CST)

Good points there AQ. It's probably reasonable (for many reasons) to treat XCom's "elite" recruits as effectively rookies when tangling with aliens and alien weapons.

Thinking about auto modes, actually it does make sense that they have better firepower than the other modes. Otherwise why would they be used at all? Auto should be more effective per unit of time, less effective per unit of ammo - which it is.

That being the case, a more moderate proposal would be to tweak the game to ensure that Kai > Ksn, i.e. Aimed fire is more effective than Snap, per unit of time. Surely that is just common sense? Otherwise there is very little reason ever to Aim.

By the way, could you expand on your thoughts about Scout/Sniper? I'm not sure I understand how this tactic gives greater weight to Aimed Fire. Are there any considerations apart from reducing friendly fire and enemy reaction fire?

[[User:Spike|Spike]] 09:32, 11 November 2008 (CST)

: One additional benefit I can see for using the scout/sniper strategy other than the benefits already mentioned would be the fact that the sniper will not have to move as much, if at all. Therefore the sniper will have more TUs available to make aimed shots. Obviously this means nothing for some weapons that can only be fired once per turn on aimed, but for weapons that can be aimed several times, then every extra TU helps. Just as snaps and auto shots bank on extra attempts to improve their odds of success, the same can apply to aimed shots too. -[[User:NKF|NKF]] 22:38, 12 November 2008 (CST)

In real combat, both quick and carefully aimed shots are useful depending on the situation, for at least two reasons. In situations such as an ambush, when the target is unaware of the firer, it is beneficial to hit it with the first shot, regardless or how long it may take to aim precisely, because after that the firer's position, if only approximately, will be made known to the enemy, who will then be prepared for fire from the same quarter and will seek cover and possibly fire back. This consideration can hardly be accounted for in the classic X-COM (but must be in the games it inspired).

The second reason is that snap shots are more effective at close range and aimed ones at long range. It happens because at short range the dispersion cone is much smaller than the target's angular area and aiming consists of pointing the weapon roughly at the target without the use of sights. The hit change is near 100% so the one who shorts first is the winner. At long range, however, the situation is reversed. The weapon must be aligned carefully to point at the small target and stabilized to narrow down the dispersion cone. The effect of distance is not uniform across all ranges but follows the behavior of the quantiles of the normal distribution:

[[File:HitChance1d.png|||center|||||One-dimensinal formula for hit chance]]

where Φ is the [https://en.wikipedia.org/wiki/Normal_distribution#Cumulative_distribution_function cumulative normal distribution function], ''d'' the distance to the target, and ''r'' the target's characteristic radius as projected in the firer's direction. The standard deviation σ determines the opening angle of the dispersion cone and thus the accuracy of the shot.
Here are the graphs for three different accuracies:

[[File:HitChanceVsDistance.png|center|Hit chance vs. distance]]

Precise aiming takes a certain time determined by the weapon and the firer, after which accuracy reaches a plateau and then starts to degrade due to fatigue. During the effective aiming stage the rate of accuracy increase is highest at the beginning and becomes lower at it approaches the plateau, but in the end the probability of defeating a remote target is improved out of all proportion with regard to the time spent aiming.

That being said, I don't think serious improvement is possible unless someone can change the hit-chance formula so that it will approximate, if loosely, the varying effect of distance at different ranges described above. As distance increases the effectiveness of auto- and snap shots should become lower compared to that of an aimed shot.

=Data Analysis=

OK I did some quantitative analysis and the results are not good. The ''only'' weapons for which Aimed Fire has better efficiency of Accuracy::TU compared to Snap Fire, are Rockets and the Rocket Tank. In the notation above, there are only 3 weapons for which Kai > Ksn. In most cases, Snap fire is ''considerably'' more efficient - typically around 70% more efficient. Even for the Rocket weapons, Aimed Fire is only 25% (i.e. one-quarter) more effective. For all other weapons, including HWP and alien built-in attacks, snap fire is more efficient (in terms of generating hits on the target per unit of time). Obviously it is not good to have a game mechanic that is barely used because it has no real usefulness. I guess the proposal would be to raise the efficiency level of Aimed fire, and leave Snap fire where it is now. This would be the least unbalancing change, since Aimed fire is rarely used now, and even if it was more effective, it is tactically problematic to use because of the high TU cost. Even if you adjusted all weapons so that Aimed fire was 25% more efficient than Snap fire, I doubt that would be much incentive to use Aimed fire. 50% efficiency gain would be more likely to actually create real tactical alternatives that would get used by players in the game. By way of example, this would mean increasing the based Aimed accuracy of a Laser Rifle to around 200% (for 50% TU cost; vs Snap at 65% Accuracy for 25% TU cost). [[User:Spike|Spike]] 18:17, 6 December 2008 (CST)

:There's other measures of efficiency, as well. For example, with any explosive munition, Aimed fire gets a second chance because as a general rule, you don't want an explosive going off in the wrong place. Particularly true with the Large Rocket and HC-HE. (Also somewhat of an issue with the Small Launcher, but it's mitigated because affected units are only stunned, not killed.) On a similar note, aimed is nice in Scout-Sniper so you don't shoot the spotter(The aimed guy doesn't have to move much so has lots of TUs for aimed fire.) [[User:Arrow Quivershaft|Arrow Quivershaft]] 18:27, 6 December 2008 (CST)

:: Yes I definitely agree there are non-firepower benefits of Aimed fire, that are already present in the game. As you say these include control of collateral damage (with HE or with exposed scouts), and ammo-efficient (also "opportunity-efficient") use of single-shot weapons. Fair point! Can we list out all of the non-firepower benefits? I'm really trying hard to see if it's possible to make the case that Aimed fire is not pointless, from a game design / game balance point of view. [[User:Spike|Spike]] 19:21, 6 December 2008 (CST)

:Well, one big thing is that reloading a weapon takes 15 TUs flat. This is actually a fair bit. For a rookie, it can be anywhere from 1/4th to almost 1/3rd of his full TU allotment, whereas its just below 1/5th for a top-level veteran. Any weapon with a small clip is going to require reloading on a regular basis if repeated snap fire is used. Anything with a 1-round clip counts, any arguably, so does the Heavy Cannon. (Though the Blaster Launcher has no mode other than Aimed, so is only included for example). The more ammo you use, the more you need to carry, thus the more space you need in the transport.
:A single soldier can carry, at most, 5 rockets, 7 Blaster Bombs, 66 Heavy Cannon shots(11 clips), or 25 Small Launcher rounds. (These numbers do not take into account Strength limitations, or use of the Item Stacking bug. Also note that there's no reason you should need that many Small Launcher rounds.) Consider how many spaces this is on the transport, for one. Then multiply this across the number of associated weapons...you hit 80 pretty fast. Using lots of ammo means less room on the transport for other gear. Also consider how weighted down the soldier is. A soldier hauling around a rocket launcher and 4 reloads is carrying 50 units of weight, leaving not much room for other gear.
:The collateral damage is an issue that needs to be watched for, of course. Snap-firing a Large Rocket can kill large portions of your team if not done properly. Even if none of your soldiers are killed, you may destroy valuable equipment if not careful. (Especially true near UFO power sources!) And at range, snap fire's path can intersect the position of a soldier.
:Cost is yet another. In particular, in the case of the Small Launcher, ammunition requires Elerium to manufacture. And Large Rockets don't come too cheap if you're firing them off willy-nilly.
:And finally, when dealing with the tanks, the Ammo problem is even worse...you CAN'T reload in the middle of battle; you get one magazine and that's it. (This is only truly relevant for the Rocket Tank and Fusion Hovertank.) Plus ammo is even more expensive!
:There was another idea I had, but it escapes me currently. Still, I think this is a fairly comprehensive list. [[User:Arrow Quivershaft|Arrow Quivershaft]] 20:18, 6 December 2008 (CST)

=TU Efficiency Table=

The table below shows the extent to which Aimed fire is less efficient than Snap fire. A value of 50% would mean Aimed fire is half as efficient (in terms of accuracy:TU) as Snap fire. The table also shows what the required value of Aimed Accuracy % would need to be increased to, in order to make Aimed fire as efficient (100%) as Snap fire, or 125% as efficient, or 150% as efficient.

See also the [[Firepower Tables]] which show how ineffective Aimed fire is in terms of damage-on-target. The root cause of the damage-on-target inefficiency, is this TU inefficiency.

<table {{StdCenterTable}} class="sortable">
<caption><b>Aimed vs Snap fire - Accuracy::TU Efficiency<br>with corrective values for Aimed Accuracy
</b></caption>
<tr {{StdDescTable_Heading}}>
<th>Weapon</th><th>Aim Acc%</th><th>Aim:Snap</th><th>100%</th><th>125%</th><th>150%</th>
<tr><td>Pistol</td><td>78</td><td>78%</td><td>100</td><td>125</td><td>150</td></tr>
<tr><td>Rifle</td><td>110</td><td>57%</td><td>192</td><td>240</td><td>288</td></tr>
<tr><td>HC - AP</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>HC - HE</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>AC - AP</td><td>82</td><td>60%</td><td>136</td><td>170</td><td>204</td></tr>
<tr><td>AC - HE</td><td>82</td><td>60%</td><td>136</td><td>170</td><td>204</td></tr>
<tr><td>RocketSm</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>RocketLg</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>LaserP</td><td>68</td><td>62%</td><td>110</td><td>138</td><td>165</td></tr>
<tr><td>LaserR</td><td>100</td><td>77%</td><td>130</td><td>163</td><td>195</td></tr>
<tr><td>HvyLas</td><td>84</td><td>74%</td><td>114</td><td>142</td><td>170</td></tr>
<tr><td>HvyLas (XCU)</td><td>110</td><td>81%</td><td>136</td><td>170</td><td>205</td></tr>
<tr><td>PlasmaP</td><td>85</td><td>65%</td><td>130</td><td>163</td><td>195</td></tr>
<tr><td>PlasmaR</td><td>100</td><td>58%</td><td>172</td><td>215</td><td>258</td></tr>
<tr><td>HvyPlas</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Blast Bmb</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td></tr>
<tr><td>Stun Bmb</td><td>110</td><td>90%</td><td>122</td><td>152</td><td>183</td></tr>
<tr><td>Tk Cannon</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>Tk Rocket</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>Tk Laser</td><td>85</td><td>75%</td><td>114</td><td>142</td><td>170</td></tr>
<tr><td>Tk Plasma</td><td>100</td><td>59%</td><td>170</td><td>213</td><td>255</td></tr>
<tr><td>Tk Fusion</td><td>100</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td></tr>
<tr><td>Cyberdisc</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Celatid</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Sectopod</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>

</table>

=TU Efficiency Mods=

The following replacement OBDATA.DAT files implement the principle that Aimed fire should not be less efficient than Snap fire. To use these, make a safe copy of your original OBDATA.DAT in the GEODATA folder, then replace it with one of these files. You should see the new improved base accuracies (and in some cases reduced TU costs) in the in-game UFOPaedia.

* [[Media:OBDTU100.DAT]] fixes Aimed fire so it is exactly as efficient as Snap fire.
* [[Media:OBDTU125.DAT]] fixes Aimed fire so it is 125% more efficient then Snap fire. This is the same ratio between Snap and Aimed fire that exists for Rockets.
* [[Media:OBDTU150.DAT]] fixes Aimed fire so it is 150% more efficient then Snap fire. This is probably over-powerful, and too unbalancing in the other direction. Also, in some cases (Rifle and Plasma Rifle) it is necessary to reduce the TU cost of Aimed fire slightly, as otherwise Accuracy would need to be raised above 255% (not possible as it is held in a single unsigned byte).

[[Category:Enemy Unknown/UFO Defense]]

File:HitChance1d.png

2016-09-01T15:03:45Z

Ant 222: The one-dimensional formula for hit chance. Phi is the cumulative normal distribution, d distance to the target, and r the target's characteristic radius. Standard deviation sigma determines the accuracy of the shot.

The one-dimensional formula for hit chance. Phi is the cumulative normal distribution, d distance to the target, and r the target's characteristic radius. Standard deviation sigma determines the accuracy of the shot.

Accuracy vs TU Efficiency

2016-09-01T11:58:20Z

Ant 222:

In almost every case (Rockets are the exception), Snap fire is a more efficient use of TUs than Aimed fire. This means Aimed fire is not useful apart from certain specialised activities.

=Proposal=

Would it be unreasonable to correct the TU and/or accuracy values of weapons, so that if we call the efficiency (hits per unit of time)

K = accuracy/TUs

and we have

Kai (K - Aimed)
Ksn (K - Snap)

we correct the game tables to ensure that for any given weapon:

Kai > Ksn

In English, we are saying that extra time spent on aiming is no less useful than time spent snap firing. Or, if I spend twice as long on an aimed shot than on a snap shot, my chance of hitting should be doubled.

( In an unmodified game, this relationship does not hold, for all cases except Rockets. )

The purpose of this modification would be to ensure that, in terms of delivering hits to the target per unit of time, Aimed fire is more effective than Snap fire, which in turn is more effective than Auto fire.

Otherwise there are few reasons not always use the fastest available fire rate.

(3 reasons I can think of are:

* Conserving ammo - often of minor importance, except with single launcher rounds (Rockets etc), especially rare/expensive ones such as Blaster Bombs.
* Avoiding "collateral damage" to friendly troops, civilians, or valuable recoverable items
* "First shot kill" - killing the target before it can reaction-fire

But for general combat, there is often no reason to prefer Aimed fire over Snap, or Snap over Auto.

=Discussion=

Analysis of 20th century battles showed that ordinary soldiers were more effective at killing the enemy when they were given automatic weapons. Resistance to equipping troops with full auto small arms as standard was mainly on ammunition cost grounds (as well as conservatism). This was further refined by studies showing that a burst mode (as used in XCom) was optimum.

However, this was true only for the ordinary troops, who were found to be too unsettled by combat to fire in a controlled fashion. For the minority who had the presence of mind to fire under control, taking slow, carefully aimed shots was more effective and this is where the bulk of the overall effective firepower of an entire formation would come from.

Now, which group do we think XCom soldiers fall into?

[[User:Spike|Spike]] 13:28, 10 November 2008 (CST)

:X-COM soldiers are selected as the best available volunteers from the various militaries of the funding nations, according to backstory. Thus they'd probably be more geared towards the latter class. However, given the...shall we say...less-than-ideal stats of some recruits, its clear that even then that's not going to hold. Bravery would probably be one of the main stats applicable to this argument. It should also be noted that X-COM soldiers are fighting a completely different war, one which could well make most regular soldiers break down from the stress alone. Think about it, for the first half of the game, at least, X-COM soldiers are out-equipped, fighting ALIENS, some 4 times thier own size, who can kill them in one glancing hit from a PLASMA weapon, while they themselves have trouble even hurting some of them, and whom are coming from OUTER SPACE in UFOs they can't scratch on the ground and which can VAPORIZE F-22s(or whatever the Interceptor is). That's not even mentioning the funding issues, terror attacks, or psychological scarring. And every time the Skyranger goes out, they can pretty much count on the fact that at least 2 or 3 of the people they're inside it with will be coming back to base in a body bag. This is liable to put ANYONE, even a battle-hardened combat vet of a normal earth military, off balance, at the very least. Which can be seen in how rapidly X-COM recruits tend to panic when things go bad. Overall troop morale would be one X-COM's (or any such organization's) greatest problems.

:As for the use of aiming/snap/auto, it's basically been established that in UFO, auto reigns supreme. Whereas in TFTD, auto fire is only available on a handful of weapons, with horrendous accuracy for it, and usually with a fairly small clip. I don't know how many Aquanauts I've had run dry on ammo at a critical moment because I used the Jet Harpoon's Autofire too liberally(read: use at all) TFTD's weapons, however, have awesome Aimed accuracy stats, swinging it in the opposite direction of UFO; aimed is the prefered fire of choice. Also, perhaps use Scout/Sniper some more if you want to use Aimed mode; it increases overall safety. :) [[User:Arrow Quivershaft|Arrow Quivershaft]] 13:50, 10 November 2008 (CST)

Good points there AQ. It's probably reasonable (for many reasons) to treat XCom's "elite" recruits as effectively rookies when tangling with aliens and alien weapons.

Thinking about auto modes, actually it does make sense that they have better firepower than the other modes. Otherwise why would they be used at all? Auto should be more effective per unit of time, less effective per unit of ammo - which it is.

That being the case, a more moderate proposal would be to tweak the game to ensure that Kai > Ksn, i.e. Aimed fire is more effective than Snap, per unit of time. Surely that is just common sense? Otherwise there is very little reason ever to Aim.

By the way, could you expand on your thoughts about Scout/Sniper? I'm not sure I understand how this tactic gives greater weight to Aimed Fire. Are there any considerations apart from reducing friendly fire and enemy reaction fire?

[[User:Spike|Spike]] 09:32, 11 November 2008 (CST)

: One additional benefit I can see for using the scout/sniper strategy other than the benefits already mentioned would be the fact that the sniper will not have to move as much, if at all. Therefore the sniper will have more TUs available to make aimed shots. Obviously this means nothing for some weapons that can only be fired once per turn on aimed, but for weapons that can be aimed several times, then every extra TU helps. Just as snaps and auto shots bank on extra attempts to improve their odds of success, the same can apply to aimed shots too. -[[User:NKF|NKF]] 22:38, 12 November 2008 (CST)

In real combat, both quick and carefully aimed shots are useful depending on the situation, for at least two reasons. In situations such as an ambush, when the target is unaware of the firer, it is beneficial to hit it with the first shot, regardless or how long it may take to aim precisely, because after that the firer's position, if only approximately, will be made known to the enemy, who will then be prepared for fire from the same quarter and will seek cover and possibly fire back. This consideration can hardly be accounted for in the classic X-COM (but must be in the games it inspired).

The second reason is that snap shots are more effective at close range and aimed ones at long range. It happens because at short range the dispersion cone is much smaller than the target's angular area and aiming consists of pointing the weapon roughly at the target without the use of sights. The hit change is near 100% so the one who shorts first is the winner. At long range, however, the situation is reversed. The weapon must be aligned carefully to point at the small target and stabilized to narrow down the dispersion cone. The effect of distance is not uniform across all ranges but follows the behavior of the quantiles of the normal distribution:

[[File:HitChanceVsDistance.png||Hit chance vs. distance]]

Precise aiming takes a certain time determined by the weapon and the firer, after which accuracy reaches a plateau and then starts to degrade due to fatigue. During the effective aiming stage the rate of accuracy increase is highest at the beginning and becomes lower at it approaches the plateau, but in the end the probability of defeating a remote target is improved out of all proportion with regard to the time spent aiming.

That being said, I don't think serious improvement is possible unless someone can change the hit-chance formula so that it will approximate, if loosely, the varying effect of distance at different ranges described above. As distance increases the effectiveness of auto- and snap shots should become lower compared to that of an aimed shot.
[[User:Ant 222|Ant 222]] ([[User talk:Ant 222|talk]]) 11:58, 1 September 2016 (UTC)

=Data Analysis=

OK I did some quantitative analysis and the results are not good. The ''only'' weapons for which Aimed Fire has better efficiency of Accuracy::TU compared to Snap Fire, are Rockets and the Rocket Tank. In the notation above, there are only 3 weapons for which Kai > Ksn. In most cases, Snap fire is ''considerably'' more efficient - typically around 70% more efficient. Even for the Rocket weapons, Aimed Fire is only 25% (i.e. one-quarter) more effective. For all other weapons, including HWP and alien built-in attacks, snap fire is more efficient (in terms of generating hits on the target per unit of time). Obviously it is not good to have a game mechanic that is barely used because it has no real usefulness. I guess the proposal would be to raise the efficiency level of Aimed fire, and leave Snap fire where it is now. This would be the least unbalancing change, since Aimed fire is rarely used now, and even if it was more effective, it is tactically problematic to use because of the high TU cost. Even if you adjusted all weapons so that Aimed fire was 25% more efficient than Snap fire, I doubt that would be much incentive to use Aimed fire. 50% efficiency gain would be more likely to actually create real tactical alternatives that would get used by players in the game. By way of example, this would mean increasing the based Aimed accuracy of a Laser Rifle to around 200% (for 50% TU cost; vs Snap at 65% Accuracy for 25% TU cost). [[User:Spike|Spike]] 18:17, 6 December 2008 (CST)

:There's other measures of efficiency, as well. For example, with any explosive munition, Aimed fire gets a second chance because as a general rule, you don't want an explosive going off in the wrong place. Particularly true with the Large Rocket and HC-HE. (Also somewhat of an issue with the Small Launcher, but it's mitigated because affected units are only stunned, not killed.) On a similar note, aimed is nice in Scout-Sniper so you don't shoot the spotter(The aimed guy doesn't have to move much so has lots of TUs for aimed fire.) [[User:Arrow Quivershaft|Arrow Quivershaft]] 18:27, 6 December 2008 (CST)

:: Yes I definitely agree there are non-firepower benefits of Aimed fire, that are already present in the game. As you say these include control of collateral damage (with HE or with exposed scouts), and ammo-efficient (also "opportunity-efficient") use of single-shot weapons. Fair point! Can we list out all of the non-firepower benefits? I'm really trying hard to see if it's possible to make the case that Aimed fire is not pointless, from a game design / game balance point of view. [[User:Spike|Spike]] 19:21, 6 December 2008 (CST)

:Well, one big thing is that reloading a weapon takes 15 TUs flat. This is actually a fair bit. For a rookie, it can be anywhere from 1/4th to almost 1/3rd of his full TU allotment, whereas its just below 1/5th for a top-level veteran. Any weapon with a small clip is going to require reloading on a regular basis if repeated snap fire is used. Anything with a 1-round clip counts, any arguably, so does the Heavy Cannon. (Though the Blaster Launcher has no mode other than Aimed, so is only included for example). The more ammo you use, the more you need to carry, thus the more space you need in the transport.
:A single soldier can carry, at most, 5 rockets, 7 Blaster Bombs, 66 Heavy Cannon shots(11 clips), or 25 Small Launcher rounds. (These numbers do not take into account Strength limitations, or use of the Item Stacking bug. Also note that there's no reason you should need that many Small Launcher rounds.) Consider how many spaces this is on the transport, for one. Then multiply this across the number of associated weapons...you hit 80 pretty fast. Using lots of ammo means less room on the transport for other gear. Also consider how weighted down the soldier is. A soldier hauling around a rocket launcher and 4 reloads is carrying 50 units of weight, leaving not much room for other gear.
:The collateral damage is an issue that needs to be watched for, of course. Snap-firing a Large Rocket can kill large portions of your team if not done properly. Even if none of your soldiers are killed, you may destroy valuable equipment if not careful. (Especially true near UFO power sources!) And at range, snap fire's path can intersect the position of a soldier.
:Cost is yet another. In particular, in the case of the Small Launcher, ammunition requires Elerium to manufacture. And Large Rockets don't come too cheap if you're firing them off willy-nilly.
:And finally, when dealing with the tanks, the Ammo problem is even worse...you CAN'T reload in the middle of battle; you get one magazine and that's it. (This is only truly relevant for the Rocket Tank and Fusion Hovertank.) Plus ammo is even more expensive!
:There was another idea I had, but it escapes me currently. Still, I think this is a fairly comprehensive list. [[User:Arrow Quivershaft|Arrow Quivershaft]] 20:18, 6 December 2008 (CST)

=TU Efficiency Table=

The table below shows the extent to which Aimed fire is less efficient than Snap fire. A value of 50% would mean Aimed fire is half as efficient (in terms of accuracy:TU) as Snap fire. The table also shows what the required value of Aimed Accuracy % would need to be increased to, in order to make Aimed fire as efficient (100%) as Snap fire, or 125% as efficient, or 150% as efficient.

See also the [[Firepower Tables]] which show how ineffective Aimed fire is in terms of damage-on-target. The root cause of the damage-on-target inefficiency, is this TU inefficiency.

<table {{StdCenterTable}} class="sortable">
<caption><b>Aimed vs Snap fire - Accuracy::TU Efficiency<br>with corrective values for Aimed Accuracy
</b></caption>
<tr {{StdDescTable_Heading}}>
<th>Weapon</th><th>Aim Acc%</th><th>Aim:Snap</th><th>100%</th><th>125%</th><th>150%</th>
<tr><td>Pistol</td><td>78</td><td>78%</td><td>100</td><td>125</td><td>150</td></tr>
<tr><td>Rifle</td><td>110</td><td>57%</td><td>192</td><td>240</td><td>288</td></tr>
<tr><td>HC - AP</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>HC - HE</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>AC - AP</td><td>82</td><td>60%</td><td>136</td><td>170</td><td>204</td></tr>
<tr><td>AC - HE</td><td>82</td><td>60%</td><td>136</td><td>170</td><td>204</td></tr>
<tr><td>RocketSm</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>RocketLg</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>LaserP</td><td>68</td><td>62%</td><td>110</td><td>138</td><td>165</td></tr>
<tr><td>LaserR</td><td>100</td><td>77%</td><td>130</td><td>163</td><td>195</td></tr>
<tr><td>HvyLas</td><td>84</td><td>74%</td><td>114</td><td>142</td><td>170</td></tr>
<tr><td>HvyLas (XCU)</td><td>110</td><td>81%</td><td>136</td><td>170</td><td>205</td></tr>
<tr><td>PlasmaP</td><td>85</td><td>65%</td><td>130</td><td>163</td><td>195</td></tr>
<tr><td>PlasmaR</td><td>100</td><td>58%</td><td>172</td><td>215</td><td>258</td></tr>
<tr><td>HvyPlas</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Blast Bmb</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td></tr>
<tr><td>Stun Bmb</td><td>110</td><td>90%</td><td>122</td><td>152</td><td>183</td></tr>
<tr><td>Tk Cannon</td><td>90</td><td>62%</td><td>145</td><td>182</td><td>218</td></tr>
<tr><td>Tk Rocket</td><td>115</td><td>125%</td><td>92</td><td>115</td><td>138</td></tr>
<tr><td>Tk Laser</td><td>85</td><td>75%</td><td>114</td><td>142</td><td>170</td></tr>
<tr><td>Tk Plasma</td><td>100</td><td>59%</td><td>170</td><td>213</td><td>255</td></tr>
<tr><td>Tk Fusion</td><td>100</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td></tr>
<tr><td>Cyberdisc</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Celatid</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>
<tr><td>Sectopod</td><td>110</td><td>73%</td><td>150</td><td>188</td><td>225</td></tr>

</table>

=TU Efficiency Mods=

The following replacement OBDATA.DAT files implement the principle that Aimed fire should not be less efficient than Snap fire. To use these, make a safe copy of your original OBDATA.DAT in the GEODATA folder, then replace it with one of these files. You should see the new improved base accuracies (and in some cases reduced TU costs) in the in-game UFOPaedia.

* [[Media:OBDTU100.DAT]] fixes Aimed fire so it is exactly as efficient as Snap fire.
* [[Media:OBDTU125.DAT]] fixes Aimed fire so it is 125% more efficient then Snap fire. This is the same ratio between Snap and Aimed fire that exists for Rockets.
* [[Media:OBDTU150.DAT]] fixes Aimed fire so it is 150% more efficient then Snap fire. This is probably over-powerful, and too unbalancing in the other direction. Also, in some cases (Rifle and Plasma Rifle) it is necessary to reduce the TU cost of Aimed fire slightly, as otherwise Accuracy would need to be raised above 255% (not possible as it is held in a single unsigned byte).

[[Category:Enemy Unknown/UFO Defense]]

File:HitChanceVsDistance.png

2016-09-01T11:52:05Z

Ant 222: Ant 222 uploaded a new version of "File:HitChanceVsDistance.png"

A graph showing the dependency of hit chance on distance for different values of accuracy or narrowness of the dispersion cone.

File:HitChanceVsDistance.png

2016-09-01T11:39:05Z

Ant 222: A graph showing the dependency of hit chance on distance for different values of accuracy or narrowness of the dispersion cone.

A graph showing the dependency of hit chance on distance for different values of accuracy or narrowness of the dispersion cone.

Overwatch (EU2012)

2016-09-01T10:08:18Z

Ant 222: into of the deadliest units -> into *one* of the deadliest units

A soldier or alien with a remaining action can enter Overwatch (default hotkey Y). This ends the soldier's turn, but allows them to shoot at the first enemy that moves without any [[Cover (EU2012)|cover]] within their vision range during the enemy turn, albeit at a [[Aim (EU2012)|Aim]] penalty and without dealing critical hits. Firing on Overwatch at Dashing units also increases the Aim penalty.

The Penalty is a 0.7 modifier for Aim for any shots. The reduced chance to hit is further reduced again to 0.5 if the target is dashing. E.g., a soldier with 100 Aim has a 70% Chance to Hit on Overwatch, further reduced to 50% with a dashing target.

Some [[Classes_(EU2012)|class abilities]] alter or improve various aspects and properties of Overwatch. These include Close Combat Specialist ([[Assault_(EU2012)|Assault]]), Rapid Reaction ([[Heavy (EU2012)|Heavy]]), Squadsight ([[Sniper (EU2012)|Sniper]]), Opportunist ([[Sniper (EU2012)|Sniper]]), Covering Fire ([[Support (EU2012)|Support]]), and Sentinel ([[Support (EU2012)|Support]]). While using Suppression the unit will also be given an Overwatch shot if the target tries to move.

==Purposes==
Overwatch can serve two tactical purposes:
*'''To keep an enemy unit pinned down or risk a reaction shot'''
**To keep them from occupying key positions that allow them to flank your own units or better firing positions.
*'''To ambush unseen enemy units as they walk into the soldier's field of vision'''
**To cover chokepoints such as corridors and flanks.
**To shoot at just-activated alien packs before they reach cover after opening doors or stepping (with another unit) into their line of sight.

==Overwatch and Reaction Fire==
The differences between Overwatch and the [[Reaction fire triggers|Reaction Fire]] mechanic from the older games are:
* A unit must be specifically ordered to enter Overwatch every turn you want it used - simply leaving units with spare actions when ending turn will not allow them to fire on enemies (the only exception being when an enemy moves within the four-tile range needed to trigger a Close Combat Specialist [[Assault_(EU2012)|Assault]], who will then fire ''even if'' his weapon is empty). Reaction Fire, on the other hand, can only be prevented by draining a unit of [[Time Units]], moving it where it can't see enemies off-turn, or by specifically disarming it.
* Overwatch is only triggered by enemy movement, not attacks, unless the overwatcher is a [[Support (EU2012)|Support]] with the Covering Fire ability. On Reaction Fire the unit would fire at all sorts of actions (firing, moving, kneeling, etc.)
* Overwatch will only fire once, regardless of how many actions the unit still had left and it needs to be specifically activated. On Reaction Fire unit could automatically fire as many shots as long as they had Time Units left. On Overwatch it is required for the soldier to have any of these abilities to be able to fire more than one shot: Sentinel ([[Support (EU2012)|Support]] class), Rapid Reaction ([[Heavy (EU2012)|Heavy]]) or Close Combat Specialist ([[Assault_(EU2012)|Assault]]).
* Overwatch, when active, will always fire the very moment an enemy moves into a valid position to fire at. Reaction Fire, on the other hand, may not occur if the moving unit has higher [[Time_Units|TU]] and/or [[Reactions]] figures (keeping in mind Time Units were reduced with every tile travelled). It also allowed most forms of movement to be made safely behind a guarding unit so long as he wasn't facing in the required direction to see it.
* All available units on Overwatch will fire on an enemy the moment they see it - at once. This is only time in the game multiple units may perform simultaneous attacks. Reaction Fire may only be performed by one unit at a time, meaning multiple shots are never "wasted" on units who only need one to go down.

* NOTE that a unit moving to a square that an enemy unit on Overwatch can see, will NOT trigger a shot if it's the last square of movement. This means you can, and aliens frequently will, sneak up to a corner, not trigger Overwatch fire, and proceed to murder with extreme prejudice. Less frequently, you can jump up, climb up, or drop down, and then stop and shoot, as long as the square being moved to is the last square of movement, and the only square in line of sight of the Overwatching unit.

==Tips==
* NOTE that the only way to take an alien out of Overwatch is to kill it or suppress it. Blowing them up or shooting them does not remove Overwatch.
* Moving into an Overwatching unit's line of sight doesn't trigger a shot unless you ''continue'' moving. Stepping up to a corner of a building, for example, will allow you to see what's around it without drawing fire - be wary of laying Overwatch traps for enemies on such spots, as they'll instead use it as an excuse to take a free flanking shot on you.
* When Overwatching be aware of what accuracy percentage you are likely to get. It is better to hunker down and double your defense bonus rather than risk missing with a 20% shot. Especially early on, when fielding rookies with low accuracy and weak weapons, it isn't worth the risk.
* The Opportunist perk turns a Squad Sight [[Sniper (EU2012)|Sniper]] into one of the deadliest units in the game by removing the Aim penalty and allowing for critical hits, and is also a great lookout for stopping enemy thrusts with one shot.
** Overwatch is probably a good idea if your Squadsight Sniper can't draw line of sight to an enemy, but has been otherwise attacking with Squadsight. Since the enemies can't see the Sniper, and thus won't know that you've activated Overwatch, there's a much better chance of the Overwatch triggering.
***However, in [[XCOM: Enemy Within DLC (EU2012)|Enemy Within]], a sniper triggering Overwatch through Squadsight can no longer score critical hits, making this somewhat less useful.
* Close Combat Specialist gives as many shots as enemies step into less than four squares of the [[Assault_(EU2012)|Assault]]. This ability also gives Overwatch shots during your turn so it can be used by shooting at [[Muton (EU2012)#Muton Berserker|Beserkers]] (who get to take an instant, free non-attack move upon taking damage) and lead them in the direction of a unit with the perk.
* The most efficient way to deploy a wall of Overwatch shooters is to place them staggered so that they'll fire separately at the alien rather than all of them spotting it and shooting at the same time. This also allows them to fire at different aliens rather than only engaging one out of a set of multiple attackers. However, in some situations it may be more worthwhile to focus all shots at the same time to drop better-armored targets (such as [[Sectopod_(EU2012)|Sectopods]]).
* Due to the aim penalty, Overwatch can be more effectively used to "pin down" aliens while your squad manoeuvres, rather than for direct damage. An aliens will never (or very rarely) move if it sees an agent enter Overwatch (this holds true for aliens under suppressing fire as well). This can be exploited to great effect: it allows you to move your agents into flanking positions, while at the same time preventing the aliens from doing the same to you. Please note that aliens that do NOT see the agent go into Overwatch will still freely move, and will more than likely trigger a reaction shot. If all your squad's reaction shots are triggered, then the aliens will once again move freely, so care must be taken when setting them up for this tactic.
* On PC versions, there is a manipulatable bug with Overwatch, that can be of particular use to Squadsight (ie; Not-Snapshot) Snipers (or any trooper with an empty primary weapon) that involves going into Overwatch while the soldier is holding their pistol weapon. To trigger the bug, either manually reselect the Overwatching soldier and switch their weapon back to the primary, or use the hotkey to command that soldier into overwatch, and quickly click on the primary weapon icon in the bottom left corner before the camera moves on.
* In vanilla Enemy Unknown, there is an AI glitch for aliens: if they see two or more in-cover soldiers, at least one is flanking them, and they see either one go into overwatch, their AI locks up and they'll skip their next action. This is an excellent method to close in for a [[Arc_Thrower_(EU2012)|stun]], or to bring a lower-level soldier around to score a kill for XP.
** This is 'fixed' in Enemy Within: aliens and EXALT agents will most often move and risk non-Crit Overwatch damage rather than take flanking Crit shots.

== See Also ==
{{Gameplay_Mechanics_(EU2012)_Navbar}}

[[Category: Enemy Unknown (2012)]]
[[Category:Gameplay Mechanics (EU2012)]]