BumpNormals

Use a 2D single channel image to add bump to a 3D render of normal vectors.  The result can be used to affect relighting.

A UV render is required in order to remap the input image to the 3D render.  The intermediate step of converting the bump value to xy vectors happens in 2D and is then UV mapped.  This means the vector is correctly multiplied with the normal along the surface tangents and gives a better result.