I released a new plugin for Cinema R12/13 Win (currently no Mac Version available), the
Art on Bit - Surface Curvature Shader!
Here a quote from my homepage:
Create dirt maps of all kinds! With the full angle control combined with wind, you can distribute dirt, scratches, rust or abrasion regions, wherever you need them.
The settings of the shader:
If you want to know more, there are some screencasts and images on my hompage:
Surface Curvature Shader
Here is the manual to it:
Attached are two renderings made by John Strieder with the AoB - Surface Curvature Shader: