How to make invisible box (brush)?

[daemonicky]

I want to make invisible brush to do dynamic collision with player. But I do not know how to do it. I tried to set model to empty string but it removes the collisions as well. Is there another way?

[mh]

A clip brush should do it. Just set all textures to clip (it should be in your wad file, add one called "clip" if not) and the brush will be invisible and collide. Not sure how well that works with a moving brush model, but if your engine of choice includes .alpha support you could set alpha to 0 for the entity and get much the same effect.

[daemonicky]

A clip brush should do it. Just set all textures to clip (it should be in your wad file, add one called "clip" if not) and the brush will be invisible and collide. Not sure how well that works with a moving brush model, but if your engine of choice includes .alpha support you could set alpha to 0 for the entity and get much the same effect.

It works for normal brush. But for entity brush I am getting "Entity with no valid brushes or textures on line ..." .
Maybe there is some bsp compiler which can supress it.

[daemonicky]

Second approach worked. Transparency needs to be different from 0, so something like 0.01 is fine and it works. Thanks.