Material ID Shows Up All Black

[igendreau]

I'm trying to use Material ID so that I can easily select portions of my rendering for cropping/photoshopping purposes. I'm using VRay 3.6 with Sketchup 18.

Under each material, in Material Options > ID Color, I have a different bright color (blues, purples, yellows, etc...). Under Render Elements, I have Material ID included, along with Denoiser.

But when my render finishes and I select MaterialID from the dropdown menu, that version is just straight black. Am I doing something incorrect? Selecting Denoiser from the dropdown shows the attached just fine, but only black for Material ID.

Any help is much appreciated. Thanks!

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[valerostudio]

Are you using GPU rendering? If so, you cant get a MatID with GPU - yet.

If you arent using GPU - try to regenerate the IDS - Extensions-VRay-Tools-RandomizeProjectMaterialIds

[TeKnoel]

You can also set the Material ID color in the material options. Sometimes this field is set to black.