V-Ray Specular/ Lighting Render Element alpha blend problem

[mbrant]

I've been having a problem with both the Spec and Lighting pass in Vray when using alpha blended materials. A variety of passes are going to a Comp team for the final image but Spec and Lighting are giving me problems. The images below illustrate the problem I'm having.



The Beauty doesn't show anything odd, and looks accurate to the alpha blend material. However inside the Specular and Lighting passes the alpha blend areas seem to be adding a value on top of the existing spec and lighting values giving this bizarre blow out and ruins the pass. The far right element in the images is the way I need it to appear infront of a similar texture with Spec and Lighting values.

My understanding is that the Spec and Lighting passes are additive and the fully alpha'd areas are still getting a flat value added to them. The Material is a vray Blend using a simple ramp between the base mat with spec/reflection and a fully transparent vray Mtl.

Any help at all on this problem would be fantastic.

-mBrant

[vlado]

Can you post the scene above? It will help me reproduce the problem faster.

Best regards,
Vlado

[mbrant]

Here's the scene, thanks for any help.

-mBrant

[tashko.zashev]

Thank you for uploading the scene file for this issue.
I see that your scene renders correct in our internal builds so most probably we have fixed this at some point. Please let me know if you need this fix urgently or prefer to wait for official service pack release.

[mbrant]

We tried using the most recently released version, 3.4.04, and that still had the problem. This is definitely a fix that is needed urgently, getting a more recent internal build that has the fix would be terrific.

Thanks again for all the help,

-mBrant

[tashko.zashev]

We tried using the most recently released version, 3.4.04, and that still had the problem. This is definitely a fix that is needed urgently, getting a more recent internal build that has the fix would be terrific.

Thanks again for all the help,

-mBrant

Alright, I'll see how can we move this fix to the Stable nightly builds, but in the meantime you can send an email to support@chaosgroup with request for access to the stable nightly builds for V-Ray / Maya, if you don't have it already.
Thank you.

[mbrant]

We got access and installed the most recent nightly build and the problem is still happening.
-mBrant

[vlado]

The fix is not ported yet to the stable builds; we will write here when it is (hopefully in a day or so), so that you can get that build.

Best regards,
Vlado

[tashko.zashev]

The fix is available in the latest nightly (folder 20161025).