Here is a tutorial I wanted to do for quite some time.
For a long time now, VRay can use per object attributes to control some values. It can go far but often, this values are used in shaders. The general idea is to apply a single and unique shader to a big number of object, but that each object had some "special" attributes with value in them that will be applied to the shader. If you remember, I presented (french) a similar feature for mental ray (User Data).
But before doing that, this tutorial will explain how to export/import vrmesh then redo shader assignments directly within the vrmesh! As you can see, we have a lot to do!