As i went thru the VTM, everything worked just fine as the boulder meshes fall down to rest at the bottom. I have set the emitters "UseCollision" to TRUE so it works fine as long as the boulders hit the floor. But i couldn't help to notice that the boulders dissapear into the walls to some degree and i was wondering how i can set collision for the walls also. I tried to alter values inside the brush ("room") where the boulder fall but with no luck.

How can i prevent them from going into the walls so they will stay inside the room at all times, is it possible?