VRay 5 beta material procedural corrosion setup?

[nano]

Has anybody here done any experiments with corrosion in VRay 5 materials in FormZ? I'm looking for tips on building a procedural corroded metal or painted surface that is slightly eaten out using the edit material v5 interface in FormZ. I'll get their eventually but finding it a little tedious using just the primary edit material system currently available . I'm used to a slightly more broken down visual interface.

Here's a sample of the kind of object I'm trying to degrade - A reproduction of a c1869 French Metal Wheel Dual Velocipede.

btw - yes I know the foot pedal textures etc need rotating and resetting properly... and the wood components toned down etc... but currently working on getting the metal frame to age.

Thanks

[nano]

Ok well I've worked out a quick fix method using a combination of traditional negative bump and reflection maps and a few odd settings which at least is creating a simulation that is getting there. Attached image shows initial tests with a fairly crude set up stopped it at about pass 92 though so it's very rough still.

I'm still having issues with working through the procedural noise and combing them with the image mapping.

Is there are known rough guide for these settings for this FormZ implementation aside from the generic Chaos material?

The version 5 caustics and photon mapping are working pretty neat for helping with this type of material render and lighting etc.