I know a lot of changes have been made to the bump mapping in 2.57, but I was surprised to find that if I used a tangent space normal map for my model, then bump mapping (aka height mapping) no longer seems to work at all.
Using both a procedural bump (a clouds texture) and an image-based bump, I can apply it to my model & get the expected results. But if I then apply a T.S normal map, all the bump effect is canceled completely. Even a value as high as 10.0 in the Nor channel will not produce any visible effects from the bump map.
By contrast, if I bake a tangent normal map from an applied texture, that combines with other normal maps just fine.
I’m sure that in 2.49 and earlier I had combined both bump mapping and T.S. normal mapping successfully. Has that now changed? If so, why? It seems to limit the ways you can modify the surface relief of models.