Do Woods/Pines act as a partial shield?

[Green Hornet]

This is something I've always wondered about in both CMBO and CMBB. Although I think I know the answer, I'm not certain I'm convinced it makes sense.

Standard apologies if this has been discussed before and I just missed it in my search...

I have a unit in open terrain, but behind a patch of woods or pines such that the enemy still has LOS to my unit. When the enemy unit opens fire, does my unit gain ANY advantage from the fact that the enemy is shooting through a patch of trees? I would guess the answer is "no" and that my unit's %exposed is calculated just the same as if there were no trees between it and the enemy.

I would think the fact that, even though the enemy has LOS through the trees, my unit should still gain some type of defensive bonus due to the small percentage of bullets being deflected or stopped by the trees.

Probably too late to address in CMAK(?). Maybe something to add to CMX2. Maybe I'm wrong an it's already factored into BO and BB.

[YankeeDog]

My understanding of the game engine is that intervening cover like trees, brush, etc. does not factor into the cover rating given to a unit.

Units do, however, gain some minor advantage to having intervening cover between them and a shooter. Quality of LOS does factor into firepower calculations. So if a unit is in open ground, but has a small stand of trees between them and a shooter, the shooter will have poorer LOS (as evidenced by a darker blue line with the LOS tool), and this will reduce the effective firepower somewhat. This also affects AT shots - shots made with poor LOS are less accurate.

Of course, anything that degrades LOS, incuding darkness, rain and fog, reduces effective fp this way, so this isn't really modeling the bullet-stopping effects that intervening hard cover like trees would would have, but it does help somewhat.

It would be a tricky thing to do, but some sort of intervening cover modeling would be cool.

Cheers,

YD

[Michael Emrys]

Originally posted by YankeeDog:

It would be a tricky thing to do, but some sort of intervening cover modeling would be cool.

Why would it be tricky? You have a number for the density of the particular type(s) of intervening cover, and you have a number for the LOF through it. You multiply the two together and voila! What am I missing?

Michael

[lcm1947]

I'm sure the answer would be that it is possible for the bullet, etc to pass through said trees, brush, etc without actually hitting any of it thereby not being effected. See I'm learning.

[Michael Emrys]

Originally posted by lcm1947:

I'm sure the answer would be that it is possible for the bullet, etc to pass through said trees, brush, etc without actually hitting any of it thereby not being effected.

True of a certain portion of bullets/shells. But another portion would be deflected off their course and/or lose energy. The ratio between those two portions would be determined as outlined above.

Michael

[YankeeDog]

Because you would also have to take into account, among other things:

(1) the 'hardness' of the cover (trees deflect more bullets than bushes)

(2) the 'deflectability' of the round in question (mostly a round velocity issue, but weight of slug also plays a factor - basically heavier, faster rounds are less likely to be significantly deflected.

(3) The height of the intervening feature, height of shooter and target, and trajectory of round. For example, tall pines would have a chance of intercept virtually any realistically possible small arms trajectory, but low brush or rocks might be high enough to intercept only closer shooters, rounds shot with enough distance would having enough trajectory to clear the obstacles.

(4) The distance between the cover and the target - softer cover like brush and leaves may not actually stop bullets, but it will often deflect them or make them tumble. If the target is just behind the cover, this deflection offers little protection and can actually make the fire more effective by creating erratic trajectories. If there is some distance between the target and the deflecting cover, though, then the deflecting cover can offer considerable protection.

I suppose you could simplify things, though and just model intervening cover of trees, which would be simpler. since they're generally high enough and 'hard' enough to intercept most rounds/trajectories. The effects of other types of terrain are more minor and therefore can probably be lived without.

Cheers,

YD

[Michael Emrys]

Originally posted by YankeeDog:

Because you would also have to take into account, among other things:

(1) the 'hardness' of the cover (trees deflect more bullets than bushes)

(2) the 'deflectability' of the round in question (mostly a round velocity issue, but weight of slug also plays a factor - basically heavier, faster rounds are less likely to be significantly deflected.

(3) The height of the intervening feature, height of shooter and target, and trajectory of round. For example, tall pines would have a chance of intercept virtually any realistically possible small arms trajectory, but low brush or rocks might be high enough to intercept only closer shooters, rounds shot with enough distance would having enough trajectory to clear the obstacles.

(4) The distance between the cover and the target - softer cover like brush and leaves may not actually stop bullets, but it will often deflect them or make them tumble. If the target is just behind the cover, this deflection offers little protection and can actually make the fire more effective by creating erratic trajectories. If there is some distance between the target and the deflecting cover, though, then the deflecting cover can offer considerable protection.

Spoken like a True Grog. I'm proud of you, m'boy!

I suppose you could simplify things, though and just model intervening cover of trees, which would be simpler. since they're generally high enough and 'hard' enough to intercept most rounds/trajectories. The effects of other types of terrain are more minor and therefore can probably be lived without.

That was my starting, though unspoken, assumption (though I would like to keep all types of trees and brush, and possibly some other types of terrain as well). I would not want to make it discouraging to BFC to make a small but noticeable improvement to the game by weighting it down with a lot of burdensome complications that would likely not make any measureable difference to play.

Michael

[ September 24, 2003, 11:23 PM: Message edited by: Michael Emrys ]

[YankeeDog]

Point well taken. As my uncle once told me, just 'cause you're unlikely to get in her pants is no reason not to go for a smooch. . .

I have a wierd uncle.

Cheers,

YD

[Michael Emrys]

Originally posted by YankeeDog:

Point well taken. As my uncle once told me, just 'cause you're unlikely to get in her pants is no reason not to go for a smooch. . .

I have a wierd uncle.

Sounds more wise than weird to me.

Michael

[Green Hornet]

Good points gentlemen. Thanks for the information.

I agree that modeling some sort of interving cover would be pretty cool. If BFC could do it in such a way that kept things simple but still allowed for some type of defensive bonus, that would be my first choice.

The situation doesn't really come up that often but it does happen often enough to do some wishful thinking...

[Sergei]

Why don't you just experiment and tell us your findings? I find intervening terrain to be protective, because it makes the LOS line get darker, indicating that the exposure is lower. Or is it?

[Michael Emrys]

Well, if you have a target, you can read their exposure right off the LoS tool, so that should make for easy comparisons. Create a test map of flat, open terrain with a patch of trees. Place your squad so it can see a squad on open terrain behind the trees and another squad the same distance away but without the intervening trees.

Michael

[Green Hornet]

I was so certain that my assumption was correct, I didn't think about doing a test. Well, I just did a test and guess what?

I was wrong.

At least exposure is definitley affected by intervening cover. Admittedly, this was a quick and dirty test but it was enough to convince me that intervening cover is not completely ignored as I had thought.

Below are the % exposures when a unit is targeted through various terrain types ( some types have more data points due to the way I set things up ):

Targeting through open - 75, 75

Targeting through pines - 62, 65

Targeting through woods - 62, 59, 55, 64

Targeting through scattered trees - 66, 72, 70

The interesting thing that I noticed was that the % exposure decreased within a given terrain type as the area of the terrain through which the targeting line traveled increased.

This game is so cool. :cool:

[Michael Emrys]

It's hard to tell from the information you give, but it seems as though there isn't as much difference between the three types of trees as I would expect. What time of year did you have set? And did you think of trying it with brush?

If you are in the mood to do some more tests, it might be revealing to discover what the stats are on firepower delivered on target too. That information isn't on the LoS tool, I don't think, but it is on the targetting tool.

Michael

[Green Hornet]

I agree Michael. My test was done late last night and as I was turning in I realized I should have compared firepower as well.

For my own sake, I plan to do a more extensive, comprehensive test tonight when I get home from work (after my PBEMs, of course ). I'll share the results for those interested.

[Michael Emrys]

Splendid! I look forward to it with rapt attention.

Michael

[Green Hornet]

Okay, I had some time for a more exhaustive test. It seems that intervening cover affects % exposure but does not affect firepower.

For those interested, my test was done with German 41 rifle squads positioned exactly 97 meters from their targets (Russian inf). All squads had identical firepower potential (124 at 40m) and all HQ units had +0 combat bonuses. Season was set to summer.

Below are the results:

Terrain.....%Exposure.....Firepower

Open..............75%................87

Brush.............72%................87

Brush(x2)........68%................87

SctTrees.........66%................87

Pines.............60%................87

SctTrees(x2)....58%................87

Woods............57%................87

*(x2) indicates targeting through 2 tiles of terrain. All others are targeting through a single terrain tile.

So it seems the game models the fact that intervening cover reduces LOS and therefore exposure; but it does not reduce firepower which would indicate that it does not model munitions being deflected or stopped by trees and brush.

Hope a few folks find this interesting.

[Michael Emrys]

Exceedingly cool! :cool:

Thanks, GH, for some interesting data. That last test was done professionally!

Michael

[atiff]

But isn't *effective* firepower delivered on the target the multiple of Firepower and Exposure (or something like that)? The firepower you see on the targeting tool is based solely on range, I thought.

In that case, you are seeing the effects of hard and soft cover, it is all thrown together as "exposure".

Notice, for example, the Pine and Woods numbers (60% and 57% repsectively). Now, Pines is meant to be trees and little undergrowth, while Woods is meant to be trees with lots of undergrowth. You would imagine that it is a LOT easier to find *something* to hide behind in Woods, but for the most part the amount of hard cover (trees) is the same between Woods and Pines. This you only get a little more benefit in Woods, as the extra stuff is all "soft" cover.

Also notice the difference between Open and Brush (3%) and Pines and Woods (3%). Seems like in both cases, the difference is additional bits of soft cover (giving 3% more cover, ie not much cvoer when you are hiding behind something with no stopping power). (so Brush is Woods without the trees)

Does that make sense to anyone else? It seems to make sense to me.

[Dschugaschwili]

atiff is right here. In the example above, you would see a firepower rating of 87 even if the enemy unit was in a trench. The firepower rating in CM includes range and experience (probably also the fp bonus from HQs), but not terrain. That is covered in the exposure rating only.

Dschugaschwili

[lcm1947]

Thanks for doing the test Green Hornet. Good useful info.

[Ruthless]

Originally posted by atiff:

But isn't *effective* firepower delivered on the target the multiple of Firepower and Exposure (or something like that)? The firepower you see on the targeting tool is based solely on range, I thought.

In that case, you are seeing the effects of hard and soft cover, it is all thrown together as "exposure".

Notice, for example, the Pine and Woods numbers (60% and 57% repsectively). Now, Pines is meant to be trees and little undergrowth, while Woods is meant to be trees with lots of undergrowth. You would imagine that it is a LOT easier to find *something* to hide behind in Woods, but for the most part the amount of hard cover (trees) is the same between Woods and Pines. This you only get a little more benefit in Woods, as the extra stuff is all "soft" cover.

Also notice the difference between Open and Brush (3%) and Pines and Woods (3%). Seems like in both cases, the difference is additional bits of soft cover (giving 3% more cover, ie not much cvoer when you are hiding behind something with no stopping power). (so Brush is Woods without the trees)

Does that make sense to anyone else? It seems to make sense to me.

It makes perfect sense.

BFC model probably (this is a guess) has a table of firepower vs. range for different units and that represents the density of bullets at a particular range (SMG at close range would be very high, at long range, very low...something like that) and the exposure represents the effects of cover. So, you'd take the firepower at whatever range and combine it with the exposure value to figure out the hit probabilities.

---edited to add:

the "exposure" value also likely takes into account the units stance (running, pinned, hiding, moving...)

[ September 26, 2003, 09:52 PM: Message edited by: Ruthless ]