Extra tex -empty after first frame

[akos_kiss]

Hi!

We are rendering an animation and using the extra tex RE for some custom extra masks for a few objects (these are black and white bitmaps). The issue is that for some reason the extra tex render elements with textures only renders only on the first frame. After that the extra tex RE is just white. To work around this we use c4d standard render and some luminescent materials to get the masks but it would be great if the extra tex worked with bitmaps.

The render settings are really simple, just default with bucket rendering.
I'll attach a sample scene a bit later.

[aleksandar.kasabov]

Hello akos_kiss,

Are you rendering with V-Ray or V-Ray GPU? Can you specify the exact versions of V-Ray, Cinema4D and your OS?

Sending a test scene would really help us check this issue as I was not able to reproduce it when testing on my end. Thank you.

[akos_kiss]

Hi aleksandar.kasabov!

Sorry for the late reply but i wanted to collect a bunch of bugs i experienced during the last project.
The smal scene is available on this link.
I used c4d S26 and vray 5.20.04 nightly build form 2022.04.30. (vray_adv_52004_c4dr26_x64_31393)

[aleksandar.kasabov]

Hello akos_kiss,

Upon checking your scene it seems like this issue happens when the objects in your scene are animated. If the object is not animated, then the ExtraTex will RE will render correctly for all frames. I have reported this to our developers (bug ID: VC4D-1348 ) and I will let you know once we have any updates.

It seems like the issue only happens when rendering with V-Ray (CPU) and the current workaround would be to render the scene with V-Ray GPU.

Thank you.

[akos_kiss]

Hello aleksandar.kasabov,

Thanks for the tip! We are mostly using cpu rendering machines. Unfortunately rendering with gpu is not a viable option for us ATM. And the cloud rendering providers we use (like rebus farm), also don't support vray gpu rendering right now. Chaos cloud would probably work, but it takes hours to export a longer animation and sometimes it crashes at the end, but that is an other story.

Btw the reason we are using extra tex render element is that some times we need some custom matte elements for parts of an object or a texture. In the c4d node material editor i can make custom render elements AOV-s very well.

Unfortunately the blend material doesn't add up material id-s, an some times the material stacking is not the best workaround (although, material stacking also doesn't work with material id-s, or "add material").
For product visualisation our past workaround was to add all these extra elements like a logo matte or, text matte, or coat finish to a separate render elemet or matte and have complete control over the render in post.

We will probably render out these passes as separate renders for the time being.

[aleksandar.kasabov]

Hello akos_kiss,

We are mostly using cpu rendering machines. Unfortunately rendering with gpu is not a viable option for us ATM.

If you need to render your scene on CPU, you could render it with V-Ray GPU in CPU mode. Select V-Ray GPU engine (CUDA) and click on the Rendering Devices button. Then In the Preferences window, select your CPU and disable your GPU (if present). Please check this screenshot.

Let me know if that helps.

[akos_kiss]

Hello aleksandar.kasabov,

First of all, Thank you for taking the time to find a solution. Doesn't this setup have some kind of performance penalty? I mean running the gpu mode on the cpu. Btw we can only render these on our local machines because of the gpu settings we can't use Rebus farm for example.

I will test this workaround, but i think for production we will stick to rendering separate elements for now.

[aleksandar.kasabov]

Hello akos_kiss,

Yes, indeed the performance will suffer when rendering with V-Ray GPU in CUDA CPU as it will run the GPU code, which is not so well optimized for rendering on CPU. However, it can be used as a workaround for the issue until it is fixed.

I will keep you updated on the progress.

Thank you for your understanding and cooperation.