Shadow edge responding to bump map?

Support Materials and Textures
1

I think I know the answer to this question already (“nope”) but I’m hopeful…
Is there a setting that makes the line of a sharp shadow follow the “fake” topography of a bump map? Say, you have a bump map of a brick face UV-mapped to a flat face. A shadow cast on that face follows the face of the (flat) mesh, not the bump map, which destroys the illusion of the joints. Obviously, one could create a high-multi-res mesh and create actual joints, but that kinda jacks the vert count. Assuming the answer is no…

Having created a high-res mesh, you could then make a tangent-normal-space map (with an external program like xnormal), and UV that to a flat face…so would that give you a realistic shadow line? OR would you have to bake the face, lights and all, to get the realistic shadow?

2

To get a shadow to cast based on a texture and the effect it has on the physical geometry, I think you have to use the texture to Displace the actual surface, so that the edge is physically modified. See http://wiki.blender.org/index.php/Manual/Displacement_Maps

3

I was afraid you’d say that, but it reminded me that we can use subsurf for displacement, not just multires; that helps!