Material Random Color render element (sim. to sketchup)

[delineator]

I wanted to put in a request for a feature that would be immensely helpful for those of us using multiple vray packages. Right now, the best/quickest way to move geometry and mats from one 3d package to another is via vrscenes, most notably 3ds Max to SketchUp and back. When going from Max to SketchUp, all of the render element channels we use work, and the introduction of the new material random color to vray SketchUp ensures we can get material ID selections across platforms.

However, the inverse is not true. With materials generated in SketchUp and rendered out in Max (thru a vrscene), nothing really offers us the same functionality for selection. Cryptomattes somewhat work, but not for materials (and we can’t use crypto’s anyways because our post production is entirely in photoshop, which work terribly alongside cryptomattes right now). Multimattes and material ID’s can’t work because those rely on data generated in Max.

I’m hoping for something similar to the material random color render element to be implemented in vray for Max, so that vrscenes brought into Max can be more useful in production.

[VanWijnenVR]

This sounds exactly like the VRayRenderID pass. I use it for post processing and easy masking too. Would that fit your needs?

[delineator]

Oh no, not at all. The renderID doesn't/can't go thru an AA pass, so its super jaggy. Plus its more based on node ID's, i believe. I'm looking more for a matID that doesn't rely on matID assignments in the material editor effectively. Just like how Material Random Color works in skp.

[Joelaff]

I don't think you can do that without assigning a material ID to each material via the material editor (or script).

You could try VRayWireColor, to use the wireframe color of your objects. Of course this doesn't help with Multi-Sub-Objects.

Note MultiMatte can also use MtlId (but you still have to set the MtlIds).

[Morne]

VRay, for Sketchup, Rhino, Max, all have MtlIDs. Why can't you use the Ids and use multimatte? Is multimatte only found in VRay for Max?

The Max VRayMtl has an ID override, which has nothing to do with the Max material editor (it affectively overrides it)

Could you maybe attached a simple cube with mtlid saved out from Sketchup as a vrscene here, so I can have a look in Max for my own curiosity please?

[delineator]

Bit of a belated update (deadlines, amirite) - so this is just 3 planes with materials from skp, randomized matids **(come back to this in a second), exported to vrscene and rendered in Max. Newest versions in both. And the matID's showed up in Max for my materials, but not Marc (the default skp guy). That's weird...

So what happens is SKP/vray use colors as matID, Max/vray use numbers. You have the option to assign numbers in SKP as those feed into material multimatte channels. However, when you randomize the matID's in skp (via vray's built in tool), it just randomizes the material color, not the number. This tool is now deprecated since they released the "random material color" as one of the additional render channels in vray SKP and removed the mandatory matID functionality to streamline things (basically you can add a matID parameter manually to your material, but you don't have to).

So, partial success? At least its possible, but with a bit of extra work I suppose.