We support textures up to 4096x4096x32 with mipmapping generation support. There is no hard-coded limit, just the hardware abilities. And the texture dimensions must be a power of two (e.g. 512x128; 256x256; 1024x512; 1024x1024 ...). As for the bump mapping, this should be easy to do, maybe we should make more rendering paths. E.g. one for pre NV20, one for NV20+. I mean we could use the pixel shader support in higher GeForces to do this. -kk