Line of sight - Revision history

Hobbes: categorizing

2013-07-23T03:01:36Z

categorizing

← Older revision		Revision as of 03:01, 23 July 2013
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	* The Skyranger walls to the sides of the exit ramp do not block Sectoid reaction fire from the side. Other aliens evidently cannot infer the agent's presence from the visibility of their feet.		* The Skyranger walls to the sides of the exit ramp do not block Sectoid reaction fire from the side. Other aliens evidently cannot infer the agent's presence from the visibility of their feet.
	* Farm terrain? Regrettably, sectoids see your agents through fences far more easily than your agents see sectoids. Should the triggering agent survive the initial reaction fire through a still-intact fence, he should crouch immediately to get a visual on the sectoid.		* Farm terrain? Regrettably, sectoids see your agents through fences far more easily than your agents see sectoids. Should the triggering agent survive the initial reaction fire through a still-intact fence, he should crouch immediately to get a visual on the sectoid.

			[[Category:Enemy Unknown/UFO Defense]]

Zaimoni at 12:19, 20 November 2010

2010-11-20T12:19:23Z

← Older revision		Revision as of 12:19, 20 November 2010
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	* West wall one square north, alternately West wall one square west		* West wall one square north, alternately West wall one square west
	* West wall in own square, alternately West wall one square northwest		* West wall in own square, alternately West wall one square northwest

			== Sectoid Reaction Fire ==

			Sectoids are short. This noxiously changes their line of sight/line of fire.
			* The Skyranger walls to the sides of the exit ramp do not block Sectoid reaction fire from the side. Other aliens evidently cannot infer the agent's presence from the visibility of their feet.
			* Farm terrain? Regrettably, sectoids see your agents through fences far more easily than your agents see sectoids. Should the triggering agent survive the initial reaction fire through a still-intact fence, he should crouch immediately to get a visual on the sectoid.

Zombie: /* Blind spots around corners */ Relinking.

2009-01-02T03:54:32Z

Blind spots around corners: Relinking.

← Older revision		Revision as of 03:54, 2 January 2009
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	If you can spot an alien at the same instant it spots you, it will not fire upon you until your next action (see [[reaction fire triggers]]). This is why these blind spots are so deadly: in a mutual-visibility situation, your units would normally be allowed to fire first.		If you can spot an alien at the same instant it spots you, it will not fire upon you until your next action (see [[reaction fire triggers]]). This is why these blind spots are so deadly: in a mutual-visibility situation, your units would normally be allowed to fire first.

	Due to the large number of blind spots around corners (dependent on alien placement), there is no completely safe way to round a corner. The safest approach in most cases may be the path traced by the yellow line -- and if you have few [[TU]]s left, you should stop before reaching the green or blue X's.		Due to the large number of blind spots around corners (dependent on alien placement), there is no completely safe way to round a corner. The safest approach in most cases may be the path traced by the yellow line -- and if you have few [[Time Units]] left, you should stop before reaching the green or blue X's.

	Furthermore, certain narrow corridors inside UFOs and alien bases restrict the path you can follow, guaranteeing that you will pass through one or more blind spots. If you believe an alien is hiding around a corner, it may be best to throw a grenade around the corner and wait until the next turn to approach. A motion scanner might also come in handy, but beware false negatives... aliens sometimes don't move for long periods. This may be especially true of psi-capable aliens.		Furthermore, certain narrow corridors inside UFOs and alien bases restrict the path you can follow, guaranteeing that you will pass through one or more blind spots. If you believe an alien is hiding around a corner, it may be best to throw a grenade around the corner and wait until the next turn to approach. A motion scanner might also come in handy, but beware false negatives... aliens sometimes don't move for long periods. This may be especially true of psi-capable aliens.

Zaimoni at 18:37, 11 October 2007

2007-10-11T18:37:14Z

← Older revision		Revision as of 18:37, 11 October 2007
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	** extrapolated North wall 1 square south: blocks inbound line of sight due northeast, allows outbound line of sight due southwest (but will block your accurate shots anyway)		** extrapolated North wall 1 square south: blocks inbound line of sight due northeast, allows outbound line of sight due southwest (but will block your accurate shots anyway)

	(<i>Zaimoni: above was tested in turn-swapping mode for a Terrorship. The wording assumes that reaction shots and intentional shots are equivalent, but this is merely Occam's Razor; it really should be tested more carefully. In particular, the blind-spot diagram above isn't consistent with this testing.		(<i>Zaimoni: above was tested in turn-swapping mode for a Floater Terrorship. The wording assumes that reaction shots and intentional shots are equivalent, but this is merely Occam's Razor; it really should be tested more carefully. It is also possible that species makes a difference. In particular, the blind-spot diagram above isn't consistent with this testing.

	The door-opener x was summarily ambushed, testing was done with the live agent X		The door-opener x was summarily ambushed, testing was done with the live agent X

Zaimoni at 18:27, 11 October 2007

2007-10-11T18:27:53Z

← Older revision		Revision as of 18:27, 11 October 2007
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	Proper North and West walls have a logical thickness of 1, and belong in their square. Due to a pixel-level asymmetry, for small units:		Proper North and West walls have a logical thickness of 1, and belong in their square. Due to a pixel-level asymmetry, for small units:
	* North wall 1 square west: allows outbound line of sight/line of fire due northwest, blocks inbound line of sight due southeast		* North wall 1 square west: allows outbound line of sight/line of fire due northwest, blocks one of inbound line of sight or inbound line of fire due southeast
	** extrapolated North wall 1 square south: allows inbound line of sight/line of fire due northwest, blocks outbound line of sight due southeast		** extrapolated North wall 1 square south: allows inbound line of sight/line of fire due northwest, blocks one of outbound line of sight or outbound line of fire due southeast
	* North wall 1 square east: blocks outbound line of sight due northeast, allows inbound line of sight due southwest (but provides cover against accurate shots anyway)		* North wall 1 square east: blocks outbound line of sight due northeast, allows inbound line of sight due southwest (but provides cover against accurate shots anyway)
	** extrapolated North wall 1 square south: blocks inbound line of sight due northeast, allows outbound line of sight due southwest (but will block your accurate shots anyway)		** extrapolated North wall 1 square south: blocks inbound line of sight due northeast, allows outbound line of sight due southwest (but will block your accurate shots anyway)

	(<i>Zaimoni: above was tested in turn-swapping mode for a Terrorship. The wording assumes that reaction shots and intentional shots are equivalent, but this is merely Occam's Razor; it really should be tested more carefully.		(<i>Zaimoni: above was tested in turn-swapping mode for a Terrorship. The wording assumes that reaction shots and intentional shots are equivalent, but this is merely Occam's Razor; it really should be tested more carefully. In particular, the blind-spot diagram above isn't consistent with this testing.

	The door-opener x was summarily ambushed, testing was done with the live agent X		The door-opener x was summarily ambushed, testing was done with the live agent X

Zaimoni at 18:19, 11 October 2007

2007-10-11T18:19:02Z

@@ Line 59: / Line 59: @@
 ..__.
 ..___
-...__</pre>Aliens on the _ squares, at the same elevation, will not see the soldier even if facing him.  One square up is trickier, but generally crouching behind a full-height terrain feature works as above.
+...__</pre>Aliens on the _ squares, at the same elevation, will not see the soldier even if facing him.  (Cacti are less reliable than other features.)  One square up is trickier, but generally crouching behind a full-height terrain feature works as above.

Zombie: /* Blind spots around corners */ Changed image location

2007-05-03T19:57:29Z

Blind spots around corners: Changed image location

← Older revision		Revision as of 19:57, 3 May 2007
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	== Blind spots around corners ==		== Blind spots around corners ==
			[[image:Blind_spots.gif\|right]]
			There are cases where aliens can see around corners (and shoot at you) when you cannot see them. Unfortunately, the rules that govern this are complicated: a seemingly-identical or mirrored situation can produce different visibility for you and the alien depending on whether it is a northeastern, northwestern, southeastern, or southwestern corner. Furthermore, there are cases where you can shoot back at the alien (even though you can't see it), and other cases where you can't shoot it, even though it can shoot at you with impunity.

	There are cases where aliens can see around corners (and shoot at you) when you cannot see them. Unfortunately, the rules that govern this are complicated: a seemingly-identical or mirrored situation can produce different visibility for you and the alien depending on whether it is a northeastern, northwestern, southeastern, or southwestern corner. Furthermore, there are cases where you can shoot back at the alien (even though you can't see it), and other cases where you can't shoot it, even though it can shoot at you with impunity.
	~~[[image:Blind_spots.gif\|right]]~~
	In the diagram at right, the colored arrows represent aliens (and their facings), and the colored X's represent "blind spots" -- places where your units can be shot at by unseen aliens of the corresponding color. ''Depending on compass direction'' (only a northeastern corner is diagrammed here), some of these blind spots may not be experienced by your units.		In the diagram at right, the colored arrows represent aliens (and their facings), and the colored X's represent "blind spots" -- places where your units can be shot at by unseen aliens of the corresponding color. ''Depending on compass direction'' (only a northeastern corner is diagrammed here), some of these blind spots may not be experienced by your units.

Ethereal Cereal: /* Blind spots around corners */ tiny reword

2007-03-01T01:28:54Z

Blind spots around corners: tiny reword

← Older revision		Revision as of 01:28, 1 March 2007
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	In the diagram at right, the colored arrows represent aliens (and their facings), and the colored X's represent "blind spots" -- places where your units can be shot at by unseen aliens of the corresponding color. ''Depending on compass direction'' (only a northeastern corner is diagrammed here), some of these blind spots may not be experienced by your units.		In the diagram at right, the colored arrows represent aliens (and their facings), and the colored X's represent "blind spots" -- places where your units can be shot at by unseen aliens of the corresponding color. ''Depending on compass direction'' (only a northeastern corner is diagrammed here), some of these blind spots may not be experienced by your units.

	If you can spot an alien at the same instant it spots you, it will not fire upon you until your next action (see [[reaction fire triggers]]). This is why these blind spots are so deadly: in a mutual-visibility situation, your units would be allowed to fire first.		If you can spot an alien at the same instant it spots you, it will not fire upon you until your next action (see [[reaction fire triggers]]). This is why these blind spots are so deadly: in a mutual-visibility situation, your units would normally be allowed to fire first.

	Due to the large number of blind spots around corners (dependent on alien placement), there is no completely safe way to round a corner. The safest approach in most cases may be the path traced by the yellow line -- and if you have few [[TU]]s left, you should stop before reaching the green or blue X's.		Due to the large number of blind spots around corners (dependent on alien placement), there is no completely safe way to round a corner. The safest approach in most cases may be the path traced by the yellow line -- and if you have few [[TU]]s left, you should stop before reaching the green or blue X's.

Zaimoni at 23:27, 7 January 2007

2007-01-07T23:27:15Z

← Older revision		Revision as of 23:27, 7 January 2007
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	In certain cases, it is possible to see into a UFO from the outside (see [[External UFO Windows]]).		In certain cases, it is possible to see into a UFO from the outside (see [[External UFO Windows]]).

			== Orchards, Cacti, and other non-wall terrain ==

			These block line of sight much more effectively than line of fire, but are not as prone to one-way edges as walls. Examples (X is the soldier, O is the terrain; obviously, one should crouch behind half-height terrain to benefit):
			<pre>.......
			.....__
			...____
			XO_____
			...____
			.....__
			.......</pre>

			<pre>X....
			.O...
			..__.
			..___
			...__</pre>Aliens on the _ squares, at the same elevation, will not see the soldier even if facing him. One square up is trickier, but generally crouching behind a full-height terrain feature works as above.

MikeTheRed: /* Visual range */

2006-09-01T23:25:30Z

Visual range

← Older revision		Revision as of 23:25, 1 September 2006
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	Elevation does not add distance to visual range. You will see an alien on the ground when at range 20 (horizontally) and elevated 4 levels, just as you'd see him at range 20 when at ground level. Keep this in mind if stacking flying-suit shooters vertically in "alley" situations (or any other time, for that matter). But beware overhangs that might block your LOS.		Elevation does not add distance to visual range. You will see an alien on the ground when at range 20 (horizontally) and elevated 4 levels, just as you'd see him at range 20 when at ground level. Keep this in mind if stacking flying-suit shooters vertically in "alley" situations (or any other time, for that matter). But beware overhangs that might block your LOS.

	Note that "visual range of 20" is for sighting ''enemies'', the most important thing in X-COM. ''Terrain'' works slightly different. Specifically: At ground level, you see terrain to 21 tiles away, not 20 (counting from your tile as 0, as was demonstrated in inset for sighting enemies). Also, if you are elevated, the range increases by one for each level, up to 24 tiles away for 4th level. Yet this is only for terrain. You will not see enemies past 20 tiles, as explained above. It can still be useful to know, however. You may think you've visualized the whole map out to the edge, but actually you haven't swept the last few edge tiles for enemies if you are flying high and stopping as soon as you can see all the way to the edge. Then again, it's unlikely that an alien is there and/or doesn't wander into view around the time you're checking it out. An exception exists with several arctic map [[Module\|tilesets]], where puddles have the potential to trap non-flying aliens. Also known as: if you can't find the last alien on an arctic map when you thought you'd checked the whole thing, double-check corners or other edges where tilesets have made "traps".		Note that "visual range of 20" is for sighting ''enemies'', the most important thing in X-COM. ''Terrain'' works slightly different. Specifically: At ground level, you see terrain to 21 tiles away, not 20 (counting from your tile as 0, as was demonstrated in inset for sighting enemies). Also, if you are elevated, the range increases by one for each level, up to 24 tiles away for 4th level. Yet this is only for terrain. You will not see enemies past 20 tiles, as explained above. It can still be useful to know, however. You may think you've visualized the whole map out to the edge, but actually you haven't swept the last few edge tiles for enemies if you are flying high and stopping as soon as you can see all the way to the edge. Then again, it's unlikely that an alien is there and/or doesn't wander into view around the time you're checking it out. An exception exists with several [[Arctic_Terrain\|arctic]] map [[Module\|tilesets]], where puddles have the potential to trap non-flying aliens. Also known as: if you can't find the last alien on an arctic map when you thought you'd checked the whole thing, double-check corners or other edges where tilesets have made "traps".

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