Cover and reciprocity

[Tai Dai Cultist]

With the (semi)recent erratum making woods terrain modifiers reciprocal, I wonder if cover is also meant to be.

Is it/Should it be possible in AS to benefit from vertically natured partial cover without suffering the same cover from applying to the target?

What I'm talking about is a mech using the edge of a building for cover.  Can one draw LOS from the head/cockpit of a mini sniping around a corner in such a way to have unobstructed LOS to a target, but that target's reciprocal LOS back leaves the mech between 1/3 to 2/3 obstructed?  Can you give yourself cover using a vertical edge without also giving it to your target?

I would imagine the spirit of the rule is that no, you cannot.  However this draws a very interesting distinction from horizontally based cover, such as being behind a low building or standing in water.

[jairb]

My opinion is that it should be possible and allowed for one unit to benefit from partial cover while having clear visibility to another.

[nckestrel]

http://bg.battletech.com/forums/index.php?topic=31693.msg1050956#msg1050956
Full cover is reciprocal.  If you can't see them, they can't see you.
It is possible to have partial cover one way.

[Achtung Minen!]

Wood terrain cover being reciprocal is an intersting idea. Does anyone have any insights yet about how it changes the gameplay? My suspicion is that there would be less incentive to sit in cover and more incentive to keep moving and use terrain to block enemies that you don't want to engage this turn.

[ActionButler]

http://bg.battletech.com/forums/index.php?topic=31693.msg1050956#msg1050956
Full cover is reciprocal.  If you can't see them, they can't see you.
It is possible to have partial cover one way.

Which makes perfect sense to me.  If I'm standing directly next to a waist-high wall, you can't see my legs.  If the opponent is ten feet away from me, on the other side of the wall, I (assuming no other obstructions) would have full view of the the opponent. 

[Papabees]

Which makes perfect sense to me.  If I'm standing directly next to a waist-high wall, you can't see my legs.  If the opponent is ten feet away from me, on the other side of the wall, I (assuming no other obstructions) would have full view of the the opponent.

In my experience, it has been the opposite. There was a long discussion about woods that is still hanging around somewhere. It basically ended up with a house rule that allows for a unit occupying woods to gain the benefit but not the detriment. However, the unit in the woods has to lower it's TMM by the extra cost to enter the terrain. i.e. woods adds +2 to be hit but lowers TMM by one for 1. That is the way we always play now. YMMV.

[jairb]

In my experience, it has been the opposite. There was a long discussion about woods that is still hanging around somewhere. It basically ended up with a house rule that allows for a unit occupying woods to gain the benefit but not the detriment. However, the unit in the woods has to lower it's TMM by the extra cost to enter the terrain. i.e. woods adds +2 to be hit but lowers TMM by one for 1. That is the way we always play now. YMMV.

It's a staple of real military tactics to find terrain that conceals and even partially protects you from an enemy while simultaneously giving you an open, unobstructed field of view and fire.  That capability should be modeled into the game.

I'm actually ok with the notion that a Unit could be inside the edge of woods, receive concealment but not pay a concealment penalty shooting out of the woods.  This isn't an effort to reopen another debate.  I'll play the game by whatever rules TPTB decree but the concept passes the "sniff" test for me especially for "partial cover" which is the topic of this thread.

[Sartris]

I'm actually ok with the notion that a Unit could be inside the edge of woods, receive concealment but not pay a concealment penalty shooting out of the woods.  This isn't an effort to reopen another debate.  I'll play the game by whatever rules TPTB decree but the concept passes the "sniff" test for me especially for "partial cover" which is the topic of this thread.

This is how we played until the rule change. I liked it. We did the same for partial cover. Moving into base contact with a piece of terrain that granted partial cover meant the unit was sticking its guns over the obstruction and did not have to pay the penalty. We try to play with game areas large enough to encourage flanking around dug in units to negate their terrain advantages.

[Tai Dai Cultist]

http://bg.battletech.com/forums/index.php?topic=31693.msg1050956#msg1050956
Full cover is reciprocal.  If you can't see them, they can't see you.
It is possible to have partial cover one way.

I'm going to quibble, but I want to clarify it's not because I think you're incorrect, but because I think I see a rules loophole.

It all boils down to where exactly is the point of origin for LOS.

Presumably the intent is that should be the cockpit of the mech.  But that brings up several problems.
1) Some mechs' cockpit placement is ambiguous.
2) Tank 'cockpits' totally are ambiguous.
and
3) what if something is in the way of the cockpit, but only the cockpit?  If full cover is reciprocal, then you have the Ravenous Bugblatter Beast issue.  When my mech's head is obscured, I can't see you so therefore you can't see me either!

So the way to address these problems is to ignore the cockpit as being a point of LOS origin.  But then where is it instead?  The center of the base?  That raises problems with horizontal cover... 1" terrain blocks LOS that shouldn't be blocked due to the height of a mech's head/cockpit.

Should it be the center of the base for non-mechs, and >1" above the center of the base for mechs? Maybe, but that's not what the rules say.  Should they?

[nckestrel]

That's why the errata was issued.  Normally it's what the mini sees, suggesting from its head.  And that works most of the time.
But if the target has full cover from you (regardless of what he can see), you have full cover from him (via the errata).  If all that you can see him with is from the top of your mini's head, you're going to have full cover back from him, and thus can't see him.
No you can't see me at all (you have full cover from him) but I can see you. 
 

EDIT: NM, I see I completely misinterpreted your question.  Give me a bit :)

[Tai Dai Cultist]

EDIT: NM, I see I completely misinterpreted your question.  Give me a bit :)

Yeah I do think that "if I can't see you, then you can't see me and vice versa" is not only elegant but necessary.  That wasn't the issue :)

After posting, I think I thought of something that might work after the rules saying you need to see at least 1/3 of the target:

In order to have LOS to a target, your mini must also be at least 1/3 visible to the target. 

It doesn't solve the question of point of origin completely, as it's really only setting up an infinite loop.  However, having to pass a standard of reasonableness from two points rather than one should pass both the standards of K.I.S.S. as well as solving the issue for all but the most arcane of corner cases.

[nckestrel]

Yeah I do think that "if I can't see you, then you can't see me and vice versa" is not only elegant but necessary.  That wasn't the issue :)

After posting, I think I thought of something that might work after the rules saying you need to see at least 1/3 of the target:

In order to have LOS to a target, your mini must also be at least 1/3 visible to the target. 

It doesn't solve the question of point of origin completely, as it's really only setting up an infinite loop.  However, having to pass a standard of reasonableness from two points rather than one should pass both the standards of K.I.S.S. as well as solving the issue for all but the most arcane of corner cases.

I believe that's the intention.  Setting a single point would just lead to more arguements over where that point is. (Is it different on the Stalker II than the Stalker?  What if it's a big cockpit like the Battlemaster?)
It's the "mini" that needs LOS, not a single point on the mini.  And it should be more than 1/3rd of the mini that sees the target.

[jairb]

IMO, Point of Origin for LOS should be any point on the model.  It keeps game play simple and can easily be explained by a variety of sensor placed on the 'Mech / Vehicle.  The primary function of the cockpit is the working office of the weapons platform operator.  If their Mk I Eyeball happens to ALSO have LOS through the canopy, that's icing on the cake.

Lining up an aiming reticle on synthetic vision views is just as lethal as doing so on a purely optical HUD.

[GoldBishop]

<apologies for adding late to this convo>

In my group, since most of our terrain is taller than it is long (buildings 6~10" or more, terrain stacked 3~5"), we are almost always using "vertical" cover.

The run down is a pretty simple "3 points of contact" houserule to establish cover from a particular Point of Interest.  LoS is then traced from the PoI/Target to the unit attempting to gain the cover, actively adhering to the 1/3~2/3 cover rules already established.
. Left-most point on a model/base
. Center of the model/base
. Right-most point on the model/base

As Nckestrel said [and I'll summarize], "Full Cover" is reciprocal, and "Partial Cover" is not - vertical or horizontal.  I view woods as "Obstruction" penalties, but that's a different topic ;)

I also personally believe [unit's attempting Vertical Coverage from a PoI/Target] have their damage value reduced by some margin.  My only (weak) suggestion stems from the idea that a Mech's weapon systems are primarily in the torsos/arms and, similar to Standard, a Devastator with it's twin Gauss Rifles and twin PPCs straddling a building is too broad-shouldered to bring 100% of it's weapons to bear.  (It may be our familiarity with a given model to know what CAN be brought to bear when using Vertical Cover, but I'm looking at the blanket multiplier for ease/simplicity.)
...Since 1/3 is the requirement for cover, but a given model may be able to bring as much as 1/2 of itself to bear [before losing LoS], I've toyed with the idea that "1/2" should be the damage multiplier when using Vertical Cover. ("damage reduction" is only in theory; I have not play-tested this yet with my peers)

[blackjack]

So in regard to having & not having cover on a vertical plain.....
Would both be considered to have cover in the following example?

My commando bellies up behind a (level 1) 3/4" tall building, the bad guys urbanmech is about 5" out from the far side of the building. 

In the older rules the commando would have partial but the urbie is SOL, due to being back away from the terrain.

With the current wording I have seen where both attempt to claim partial cover.
 
We use the stick at the cockpit (theoretically where the most sensors are located)of each mech as a fulcrum point with the stick or laser & if the unit up against the cover can "see" > 2/3 of the other unit then no cover.

[Lboydmsw]

So in regard to having & not having cover on a vertical plain.....
Would both be considered to have cover in the following example?

My commando bellies up behind a (level 1) 3/4" tall building, the bad guys urbanmech is about 5" out from the far side of the building. 

In the older rules the commando would have partial but the urbie is SOL, due to being back away from the terrain.

With the current wording I have seen where both attempt to claim partial cover.
 
We use the stick at the cockpit (theoretically where the most sensors are located)of each mech as a fulcrum point with the stick or laser & if the unit up against the cover can "see" > 2/3 of the other unit then no cover.

if the building isn't blocking any part of the Urby from the Commando then it is not providing partial cover.  The commando which is right next to cover has partial cover.   This stuff really isn't that hard people are just looking for ways to abuse it.  The rules are really straight forward and people are looking for grey area where there is none.  If you are playing with people who are so picky and being crappy about the rules then just don't play with them.  That makes for a toxic gaming enviornment. If it isn't partial cover it will be something else.

[nckestrel]

Nothing changed for partial cover.  The only change has been the addition of the rule saying that if the target has no line of sight to you (you have more than 2/3rds cover from him), you can't see him.  That has no effect on partial cover.

[GoldBishop]

So in regard to having & not having cover on a vertical plain.....
Would both be considered to have cover in the following example?

My commando bellies up behind a (level 1) 3/4" tall building, the bad guys urbanmech is about 5" out from the far side of the building. 

In the older rules the commando would have partial but the urbie is SOL, due to being back away from the terrain.

With the current wording I have seen where both attempt to claim partial cover.
 
We use the stick at the cockpit (theoretically where the most sensors are located)of each mech as a fulcrum point with the stick or laser & if the unit up against the cover can "see" > 2/3 of the other unit then no cover.

Line of Sight will exist because each Mech's cockpit can see the other (the building is 3/4"?  or 1", rounding up for simplicity).

Take your stick/laser, go from the Attacking Unit's Cockpit and aim for the Target's Base.  Do it again, but for Target to Attacker.
Where they touch determines cover.  Plain and simple.

In your example, the Urbanmech should be SoL (no cover, too far away) while the Commando should benefit from horizontal cover because, in my mind's eye, the Commando's base is behind the building, whereas the Urbie is "out in the open".
However, because Urbies are smaller than most other models (at least the ones I've handled), I can see that side of the argument.  I am of the opinion that a unit still needs to be adjacent to suitable cover to benefit from it (within 1" for most cases) - regardless of Alpha or Standard.

If, in your example, the Commando was instead trying to shoot around the corner of the 1" building, it will receive NO cover (neither horizontal nor vertical) because only 25% of the unit is concealed. (half of a half is less than a third).

[GoldBishop]

Seems like we're straying off topic...