I'm creating bullet penetration for thin wood and brick walls. Everything works good enough, but, I can shoot throw all walls, whatever they size is. I want to check if new position on the other side of wall, is inside solid block or not, so if it is inside solid block I will delete it. Tried to use in_solid but it doesn't work for level which is created with meshes.

I would use some flag for the wood surface and then in c_trace check it using hit

You didn't get what I'm asking for. I already do check surfaces flags and I can shoot throw them, but I want to limit wall's thickness which could be shoot throw.

trace back. if the two penetration points lie farther away than some treshold, the wall was too thick.
to check for several walls you would have to subdivide the steps.

OK, I have trace backwards, to place decal on the other side of wall, it's impossible to shoot throw several walls, only two, I'll give it a try, thanks.