matte shadow problem with SP1

[Clifton Santiago]

I went from Max 8 Vray RC2 to Max 2008 Vray 1.5 SP1 recently, and just upgraded some montaged views. Everything transitioned perfectly except for one thing: Where I have matte shadow objects (via Vray material wrapper, Matte surface, Alpha Contribution = -1) that are receiving shadows, the shadows show up in the MFB, but do not affect the alpha channel (and are subsequently lost when compositing in photoshop). They did affect the alpha channel in RC2 which was very useful. Maybe I can work around with render elements matte shadows for now. Is this a bug, or am I missing something?

[vlado]

Works fine here in a simple test... do you have the VRayMtlWrapper inside another material?

Best regards,
Vlado

[Clifton Santiago]

Nope. Just a default VrayMtl inside a VrayMtlWrapper, Matte surface, Alpha contribution=-1, in both scenes.

My scene takes a while to render, I mocked this up to reproduce the problem:

[vlado]

Did you check the "Affect alpha" option in the wrapper material? Works fine for me (see attached images), and this is in 3ds Max 2008 too.

Best regards,
Vlado

[Clifton Santiago]

Ah, thats it. Apparently when you merge a scene from 8 to 2008 (or maybe RC2 to 1.51), the affect alpha gets unchecked somehow. Thanks again Vlado! Cheers.