Creating the base for a new texture in Blender by baking an ambient occlusion map from a model of the surface. I could just as well bake a normal map from here, btw.
The AO map in Gimp blended over some basic blue texture. This is the first step, I’ll eventually follow it up with painting on scratches and adding various other layers. For technical stuff like this locker, it’s advantageous to just model the surface in Blender and bake it instead of completely hand-drawing.
I decided to turn the locker into an actual model (the middle one is a brush), because I want to be able to freely rotate it or apply physics at some point. For something like a wall panel, I would just bake the texture and be done with it, of course.
This method of texture creation gives me normal maps more or less as a byproduct, and I’ll have to inform myself about how to get them into the game. There is direct support for normal maps in q3map2, and there is deluxemapping. I guess those two are the options.
Tiny details like on the front of the locker can produce lighting artifacts with q3map2; I was able to almost get rid of them by careful placement of the props and by running my “excessive” compile script (full on radiosity and high lightmap definition).