Curvature shader

[sewer]

I need to texture some old metal objects with paint worn out. Knowing surface curvature would be perfect to map paint defects. Does anyone know a way to get curvature at given point? Some shader maybe?
Now I use mental ray shader, bake curvature to texture file and use it with vray, but that's not very convenient.

[rodeo-ny]

I think a VRay Dirt texture with "invert normal" and a small radius value should do the same thing.