VRAY render elements

[moocowfish]

Hi All, great forum !

I was hoping someone could help me, i am trying to find out if i can change the colour of the mask that is rendered when i render elements in vray 2.0.

My masks come out red, which are ok, but i would prefer straight balck and white.

thanks in advance

Rob

[muoto]

Huh...just take the "red" channel of your mask, it's just a regular "black and white" value in that red channel

[MHolmstrom]

VRay's MultiMatteElement can render 3 different masks on a single image. That's achieved by using red, green and blue. In most (or all) composition software, it's possible to select just one RGB-component and use that as a mask. In AfterEffects for example, just add Effect > Channel > Set Matte, select your MultiMatteElement as source and Red Channel as matte
You can change which ObjectIDs are rendered from Render Elements' settings and if you need more than three, you can add multiple MultiMatteElements.

In theory, it should be possible to render black and white masks with VRayMtlSelect, using a multi/sub-material with a white VRayLightMtl assigned to the material-ID of the object(s) you want to mask out and a black material on the rest. But obviously, using MaterialIDs to control masking is not as streamlined as using ObjectIDs.