.Map :: MoHAA Mapping

I know I saw a post like this somewhere but couldn't find it anymore... Sorry!
Is there something like clip textures for AIs? My AIs like disappear in the wall or you can just step into them . What do I have to change to make them solid?

Actorclip

Or Monsterclip... Its called monsterclip, but it has Actor written the tex, hehe