Multimatte Id channel inside VRayBlend mat

[Pixelab]

Now, VRay take the Material ID channel from the VRayBlend mat, it would be nice to have the option of taking the sub material of the blend and make a Multimatte with according channels

[olly]

+1

Not sure if the current setup is a bug or by design?

[smashley]

yah, i agree. Having the option of taking sub-materials of a vray blend material would be GREAT!

[ajroane]

This thread should be in the 'Problems' section, not the 'Wishlist'. I run in to this problem all the time. It would be really helpful if the Material ID's inside a VrayBlend Material could be rendered separately using a Multimatte render element. I always have to resort to slower, less convenient ways of creating blended textures in order to get separate channels for post adjustments. Does anyone know of a good work-around for this problem?

[instinct]

So it would generate semi-transparent mattes ? That would not work properly anyways because any post correction would affect both submats, just affect them less, no ?

Regards,
Thorsten

[ajroane]

I see what you're saying. It's not for blended materials in that regard. The blends use pure black and white maps, in my case, so there is no partial blending. I use the Vray Blend mostly for creating divisions between materials.

[ajroane]

I'll post a WIP image in a minute.

[ajroane]

Here's a small piece of what I'm working on right now. I have four colors of stone + grout lines that are combined in the floor tiles, decorative stone bands, and base. I created black and white alpha maps to define the stone color placement in the decorative bands, and those maps are used in my VrayBlend Material to define the material separations. I've included my material editor screen to show the layout of the large decorative band material. Each of the stone materials in the VrayBlendMtl has a different Material ID channel, but it rendered out black because the VrayBlendMtl has a channel of '0'. Is there a better way to do this? I know I could tweak the decorative map colors in Photoshop, then re-render, but I prefer to do as much as possible inside of MAX. It seems to make the post-render adjustments easier to organize.

[m_hinks]

This is exactly what I was about to post about too! We are making stripy grass patterns with the Vray Blend mat and a black and white mask, and I want to get a MultiMatte for both coloured strips of grass. Same issue, different subject!

Anybody have a solution?
Mark

[olly]

A quick workaround is to use the native max blend material.

It's not as powerful as the VrayBlendMtl , but may help you out depending on you particular situation...