Looking for procedural rusty material for VRay

[Emmanuel]

I have to render an animation of industrial objects imported from a CAD program.
Render engine will be VRay and the animation will be done in Modeler side.

The scene illustrates the replacement of old industrial structures with new ones.
The old structure should look rusty, while the new one will render as new.

There is no UV map on my imported models, so I can't use a bitmap texture to make the object look rusty.
Using a procedural shader should be fine but trueSpace's built-in shaders (marble, turbulent, granite) don't suit for a rusty look.
I tried ShaderLab but it tends to slow down VRay rendering and doesn't handle bump.

Does anyone know a third party shader that may work with VRay ? Or some trick to make non-UV-mapped objects to look rusty ?

[trueBlue]

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Also check out this Webinar
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