Jump to content

Percentages of Cover and Concealment?

Recommended Posts

I recall a very helpful post a couple of months ago that laid out the exact percentages of cover and concealment offered by each type of terrain, and I think fortifications. But now I can't find it...must not be searching the right terms. Any help?

And BTW when I ordered the Strategy Guide I kind of hoped this sort of information would be included, along with the delays of artillery FOs, things like that. Maybe the 3rd edition.

Link to comment
Share on other sites

This might be what you're looking for: From JasonC's Advanced CMBB Stratey Guide


On "Hide" or pinned behind Wall - 0% exposed

Trench, even in the open - 9%

Heavy Building - 10%

Foxhole in Wood or Pines - 14%

Wood or Pines - 15%

Light Building - 20%

Foxhole in Sc. Trees - 23%

Rubble, any type - 25%

Sc. Trees, Rough, Wall not on "Hide" - 30%

Foxhole in Open, Brush, Wheat, etc - 44%

Brush, Rocky, Cemetary - 50%

Wheat, Hedge, Wood Fence - 60%

Steppe, Marsh - 65%

Pavement - 70%

Open, Soft Ground, Wire in Sc. Trees - 75%

Wire in Open, Bridge, Ford - 100%

That doesn't quite rank them, because some give concealment and others give cover, which are different. The exposure number reflects both, but HE pays attention only to cover, trees allow airbursts to mortars and indirect artillery, buildings can be damaged or destroyed particularly by direct fire HE, etc. So, for example, foxholes in brush or wheat have about the same overall exposure number as troops in wheat without foxholes, but they are much better protected against artillery.

Also, you will see figures that differ slightly from these numbers, particularly downward, due to LOS degradation. Firing into or out of trees, or across appreciable distances of brush or wheat, deeper into rubble or rough, the LOS line is not as "clean" and the %exposed of the target will fall somewhat. The higher the original exposure number, the bigger this potential effect. So you can see some guys in brush get a 41%, when the shooter is well back into woods himself.

The truly effective forms of cover are trenches, intact heavy buildings, and foxholes reasonably deep inside woods or tall pines. The building is a bit more vunerable to direct fire HE, and the woods foxholes are more vunerable to airburst artillery. No, Virginia, trenches aren't just connected foxholes, they are way way better, and no, rubbled heavy buildings aren't still heavy building level cover, they are much worse.

But each of these is very good cover for infantry fighting. Enough so that small numbers of defenders in such positions can duke it out with superior numbers of enemies in inferior terrain and expect to prevail. Men in intact heavy buildings are receiving only half the "incoming" men in light ones or in rubble receive. Men in a trench, even in the open, will receive only a third of the fire that men approaching even through scattered trees will get from replies.

Woods and Pines are excellent cover against small arms even without foxholes, but considerably more vunerable to indirect arty or mortar fire than the low % exposure number indicates. Intact light buildings are better cover than being at the -edge- of rubble. But farther back inside rubble, they are similar. Not as good as heavy buildings by a long shot, but good cover in the overall scheme of things. And unlike the woods-pines case, more of it is "cover" rather than "concealment". A foxhole in scattered trees is about as good in pure infantry fighting terms, but more vunerable to artillery and much worse than a foxhole in full woods or pines. Each of the above can cut incoming small arms by a factor of 3 compared to open ground, which makes them effective defensive positions.

Below that level, you leave the cover good enough for defenders, and arrive at decent cover for attackers or otherwise moving troops. Obviously the woods, pines, and buildings are fine, and the place to fire-fight from, particularly if you have to take on men in trenches, heavy buildings, or wooded foxholes. But scattered trees and rough are quite good cover compared to all the worse forms of terrain, as points to make for during an approach. There is no comparison with the brush-wheat sort. The decent types will absorb half of the infantry fire troops in open ground will receive, and men in them do not get "cover panic" and change course.

Being behind a wall would be in the same category, but for the fact that the tac AI doesn't really know it has the benefit of the wall. When up and firing, men behind a wall have 30% cover, akin to the edge of scattered trees or rough. Their own LOS is completely clear. And anyone behind a wall benefits from the complete 0% exposure when they go heads-down, which they can when they pin.

Behind a wall is a very good position for panzerschrecks, because it combines perfect cover hidding, decent when up, no LOS obstactles to cut your own accuracy, and no backblast effect from being in a building. It does help if there is any moderate form of concealment or cover behind the wall, not because it combines with the wall's 30% (it won't), but because it will avoid "cover panic". Scattered trees are best, a foxhole, brush, or wheat is better than nothing.

Brush, rocky, and cemetary are better than nothing and can avoid "cove panic". But the reduction in fire compared to open ground is small, less than a factor of two. A foxhole in the open or in concealment-only terrain is similar. Of these, the foxhole is best as "cover" and the brush is worst as all "concealment" - you'd rather be mortared in foxholes than in bushes.

Think of most of these as "approach march cover" or as "open steppe, poor-man's cover". It can sometimes be worth it to use e.g. foxholes in brush in very open terrain, to avoid the predictability of placements on the limited areas of trees. Trenches are far, far superior if available, however. In large bodies, wheat is similar to brush if you stay a ways back into it, though at the edge it is considerably worse.

Below even those types, in the category of "better than nothing", come hedges and woods fences. They have the same "cover panic" issues as the wall, without any of its strength. You might be surprised that wood fences give any benefit, but they do. Think upright planks rather than three boards sideways and mostly open. Basically, a wood fence is a form of hedge, for cover purposes.

Steppe and marsh are forms of open ground, but with a bit better concealment than "open". Soft ground is the same as "open" in cover terms. Pavement, perhaps surprisingly, is no longer the "hazardous" 100% exposed terrain form it was in CMBO, but is a marginally better form of "open" than "open" is - presumably because there are things here and there to hide behind in cities, even on the streets.

Finally, there are the remaining forms of "hazardous movement" - crossing a bridge or ford, or crawling through wire. These bring 100% exposure, or 1/3rd more incoming fire than open ground. Wire placed in other forms of cover gives something akin to open ground, not full "hazardous" but not well covered either.

As you might have guessed, then, you want to be in a trench while the enemy is hung up on your wire (11 times cover differential). Or in a heavy building while the enemy is in the street outside (7 times. Or, in a pinch, in a wooded or pine foxhole while the enemy is crossing an open field (5 times).

It is worth thinking in terms of achievable local odds ratios and their relation to typical cover ratios, to see what you can expect to accomplish - in infantry vs. infantry fighting, mind - if you just have more guys to bring to the party.

Typically you can get 2:1 local infantry odds if you have the men. More than that is quite difficult, both because of global odds, and because you need to avoid bunching up too much and cover often limits the men you can get close enough to shoot at one enemy position without overcrowding.

Odds are a two-fer, because they generate twice the firepower along with twice the depth for suppression and casualties. So in principle, a 2:1 odds ratio might equalize a 4:1 cover differential. In practice, it doesn't, because the guy in the better cover is typically stationary and shooting, and some of the attackers are not firing because they are moving, while others are pinned. But 2-3:1 cover differentials, odds might handle.

That means to tackle men in trenches or heavy buildings or wooded foxholes, you need rubble or better in addition to odds - scattered trees will not cut it. Against the "second tier" of defender cover - woods or pines without foxholes, light buildings, foxholes in scattered trees, rubble - scattered trees, rough, or better will serve, while brush to wheat is marginal. This often applies in meeting engagements, when the "defender" is whoever reached the good cover first.

Men just in foxholes (or brush etc), you can defeat with odds even over open ground, provided "cover panic" doesn't completely disorganize your force, you can avoid hazardous movement or crossing wire until after gaining local fire ascendency, etc.

Trenches are quite powerful, incidentally. They do not have the direct HE weaknesses of even heavy buildings - which can draw rubbling fire even before defenders are spotted, if the attacker has enough HE ammo aboard tanks etc - or the indirect HE weakness of wooded foxholes - which are vunerable to heavy artillery airbursts, though adequate against light mortar fire. Trenches can also be placed just about anywhere (except rough etc). Concealment terrain is useful to prevent immediate ID of the trench, though a reverse slope serves that purpose just as well. Don't think they are a waste of points because you get foxholes free.

AS for craters, they seem to act like foxholes in open ground. As such, they are "approach march cover" in the scheme of things discussed above.

Link to comment
Share on other sites

Yes, thanks, that's the one I was thinking of. I wonder about one number, at least: is it true that foxholes in woods or pines only give a 1% cover bonus, compared to woods and pines w/o foxholes?

Where can I find JasonC's Advanced CMBB Strategy Guide?

[ May 30, 2003, 01:00 AM: Message edited by: SFJaykey ]

Link to comment
Share on other sites

Scattered all over, unfortunately. At best a list of links to long threads. I am considering writing up a more systematic guide and making it available like the present one. Less wordy than past posts, to make it a digestible object.

I'd cover the different troop types and typical ways to use them, and include sample QB forces (e.g. Russian 1943 cavalry combined arms for a 1500 point meeting engagement in steppe), as well as issues like this.

I'd have to charge for it to make it worth doing, though. Past posts on the forum are free, to those with the time to track them down (and read my endless prose).

Link to comment
Share on other sites

On the 1% difference between woods and woods foxholes, that is what you see with either right at the edge. Farther in, the foxhole can get down to 9-11% with LOS degradation thrown in. While without the foxhole you typically see 13% or so. That is something but still not a large effect.

The biggest advantage of the foxhole, though, is that it provides cover rather than concealment, which means it is more effective against HE. The achilles heel of woods or pines without a foxhole is indirect HE from mortars or FOs. That ignores concealment (all HE does), and in addition generates airbursts, which increase effective blast.

Against infantry and MGs, woods or pines without foxholes are great cover. Enough so that firefights between men in foxholes or trenches in addition, and men outside either of those, are basically even affairs likely to be settled by local odds or who got the first trigger pull, not by cover differences.

As a defender, you really need to stop attackers before they get into full woods or pines. If they are going to get into a given forest, you'd rather be ~200m away from that forest. Small patches you can mine or target with an HE weapon. Large ones you need to stay away from and mark with a TRP, unless you can inhabit it completely to keep all attackers out.

Link to comment
Share on other sites

Thanks for the additional comments, Jason! I should start searching under your member # when I want to find detailed answers to these questions.

If you do decide to pull together an actual guide, I'd be happy to contribute to your compensation....do you eat pizza? smile.gif

Link to comment
Share on other sites

  • 7 months later...
Originally posted by JasonC:


The biggest advantage of the foxhole, though, is that it provides cover rather than concealment, which means it is more effective against HE. The achilles heel of woods or pines without a foxhole is indirect HE from mortars or FOs. That ignores concealment (all HE does), and in addition generates airbursts, which increase effective blast.


Hi Jason,

Do you have similar statistics for cover iso concealment?



Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...