I'll stop asking so many questions eventually, I promise. Right now, I'm slightly concerned with the lighting in my map. The floor is sufficiently bright, and where it's not I can just add more, but in keeping with Valve's style I've been using solely light_spot entities. This makes the ceiling rather dark, even when I crank up the brightness to 750-1000. Here are a few pictures to show what I mean: With that out of the way, I've been brushing up on displacements in preparation for doing outdoor maps. I have the paint geometry pretty down pat, but the paint alpha stumps me. I've checked the tutorials here and none of them really detail it, and the Valve Developer's Wiki isn't much better. My problem is that clicking on the paint alpha button then on the displacement does nothing and I'm not sure what I'm doing wrong. The texture I tried to apply the alpha with was nature/blendgroundtogravel001 and the displacement texture is nature/dirtground001, if it matters. (Which it probably does.) On a final note, would it be kosher to wait until the final stages of a map to actually displace everything that's supposed to be displaced, or is it standard to apply displacements as one goes along? I ask only because I imagine it would be a bigger pain to edit displacements than to edit brushes when I inevitably decide to change the geometry.