Sorry for ressurrecting this thread, but I reall got this question right now
I have a few large models of building, and I was thinking about this, because I don’t think that an 1024 x 1024 size for almost the entire building is ok, because there would be quality hurdes due to the lack of good resolution for the numerous uv shells.
I was thinking of doing overlap, but i’ve heard that it causes issues on normal maps and lightmaps, but adding more materiais will affect performance due to the draw calls.
But i was wondering if it really does affect performance in a significant manner, or its more about a matter of loading the materiais (like borderlands) rather than a FPS hamper in-game (lets say you have a large city), I reckon that even old games such as Half Life used many materiais for the models.