Vray GPU5 and Alpha Channel

[baille_thierry]

Hello,

I realize perspectives for architects and real estate.
New year therefore new work process.

I am going from 3dsMax2019 + Vray3.6 to 3dsMax2021 + Vray5, and the task is difficult because the changes are important.

3dsMax2021 no longer supports MentalRay and I have to modify a large part of my library.

I switched to the Vray5 version to save computing time with GPU mode.
But I have a problem with transparent materials and Alpha channel. You can see the problem on the attached image.
How to solve this problem and be able to stay in GPU mode?

Thank you for your comeback.

[hermit.crab]

This is a known issue, related to the "Affect channels" options in the VRayMtl. It is already logged (internal bug-tracker id: VGPU-4147) and is already under developer investigation. No simple workaround, I'm afraid. You would need to render a second time to get the correct alpha channel (disabling all lights should make things faster).

[Micha]

I run in the situation too and ask me, could this issue not be fixed soon? It's an essential critical issue since a long time. If it can't be fixed, couldn't a kind of hybrid mode to use GPU and CPU parallel as a temporary workaround for GPU limits? A half working render engine is a bad situation.

[fixeighted]

Looking through the 'supported features' list I honestly believe it would serve customers better if there was a clear 'unsupported features' list alongside it.
People just don't imagine that an alpha channel would be unachievable - it comes as a complete surprise and the various posts about it demonstrate this I think.

I have re-read the page several times again today and can find no mention of this at all. The only mention of 'alpha channel' is noting that the 'Vray alpha' render element is unsupported.
Please correct me if I am wrong.

Currently the supported features page reads too much like a deep technical document and not one that easily lets people know whether they should
potentially waste money on cards, as I did
Sorry to be critical but transparency (pun intended) about the product is of importance I believe.

[baille_thierry]

I have been using 3dsmax and vray since 2000, and I was far from imagining that an option as essential as the Alpha channel is not offered in the GPU version ...
Continually updating requires adapting your work process , but I have never encountered such difficulties in 20 years!
At the moment I am also very disappointed with my investment in graphics cards and in the purchase of this new version of Vray.

In addition I am starting to have a lot of crashes when opening the material editor for accessing bitmaps from VRay maetrials, is this also a problem already under investigation, is this also related to the GPU version?

[hermit.crab]

There is a difference between an unsupported feature and issues such as this thread's concern. Just so you know, the issue's priority is already marked as critical and I have informed Vlado advocating the issue's prioritization.
baille_thierry Regarding the crashes, this may or may not be caused by V-Ray GPU. Best send a simple scene and reproduction method so we can take a look and confirm.