Better to render one bigger texture, or broken up textures? I mean, for example a modular model, with several mesh pieces, and occlusion culling. Wouldnt it be better to break up textures, to have one per mesh piece, since with occlusion culling, some meshes, may not be rendered? And since only a part of the texture would be for that part, you would be waistfully rendering a large texture over and over? But then again, it would be the same texture over and over if it was just one large texture.
There is a hidden benefit to using one texture for all of them that is batching, which will result in fewer draw calls (and better performance/fps) when they all need to be rendered at the same time. However, if some of the objects will be completely culled a large amount of the time, the gain may not be so noticeable.
I would imagine that for a car, for example, breaking up the tires from the main object would not be worthwhile, since although from some angles they won’t be seen, they will come into view very frequently.
However, for a large building, you would usually split the exterior from the interior.
If you have a case that is less obvious, you will probably be better off testing it with the profiler.