Alright, I investigated these curlies and those are missing faces of the second material:
Basically a lot of static models in Doom 3 have 2 materials (each applied to their own faces) and vertex color, which determines what material is to show through (so let’s say white color is material 1 and black is material 2, and anything grayscale between those edge cases will result with smooth blending between material 1 and 2).
I’ve been thinking about it and I wonder if Doom 3 map compiler strips those triangles… Gotta try loading map without that mesh to see how that works in Doom 3.
Alternatively (as an import option), maybe it would be easy to make HammUEr import FBX models? (for example if entity has “model” key with either ASE or LWO model, it would try loading FBX model instead; it would be up to designer to convert LWO and ASE to FBX) I guess it’s just more mess. I hope I can figure out if those faces are missing in .proc in original Doom 3.