3DSMAX / Vray GPU / Ornatrix Alembic / Vray Proxy

[nicolas_fuminier]

Hello,

After some intenses tests we are facing an issue with Vray GPU and Ornatrix.

The issue :
Our grooming is made in 3DSMAX Ornatrix, exported in Ornatrix ABC, imported in 3DSMAX in Vrayproxy.

At rendering time, in Vray GPU, for a image sequence, each new frame calculated with the same computer stack a new amount of VRAM cost for the hair even if the is no animation on the grooming
Exemple :
Frame 01 : VRAM Hair total : 200 MiB
Frame 02 : VRAM Hair total : 400 MiB
Frame 03 : VRAM Hair total : 600 MiB
Etc..

Linked two snapshot of two differents frame (of the same scene, with the same grooming, without any animation in the grooming)

It seems VRAY GPU can't clear the previous VRAM hair cache and stack the new one on the top of the previous cache.
Even if you stop the render, the VRAM hair cache don't clean.
Even if you start an new render without rebooting 3DSMAX, the VRAM hair still can't clear itself.
Obviously after somes frames rendered you ran out of VRAM.
The only way to restart fresh is to reboot 3DSMAX to clear the VRAM cache, and launch the render were you left it.


We've tried :
Severals builds from all the software, as many options in the Ornatrix ABC export and the VrayProxy import as we could.
Every single option we could in VRAY GPU, Brute force, Light cache, Bucket, Progressive etc.


Issue does not exist :
- In Vray CPU (with all the same settings)
- With native Ornatrix hair (we can't use that pipeline in our project, we need to use and intermediate export option)
- With Ornatrix Alembic import (we can't use that pipeline in our project because it crash when he try to convert ABC into spline with some specific grooming just before rendering)


Software :
- Windows 10 Professional 21H2
- NVIDIA STUDIO 511.65
- 3DSMAX 2021.3 up to date
- Vray GPU 5, update 2.2 up to date and some recent test with the nighly VRAY adv 52020 max2021 x64 31301
- Ornatrix_3dsmax_2021_7_7.3.3.29748 and some recent test with Ornatrix_3dsmax_2021_7_7.3.5.30081


It's also might be something to see with EPHERE, not sure about it.

Thanks for your time,
I remain fully at your disposal for any information you need,
Best,
Nicolas

[hermit.crab]

Thanks for the report. The issue is reproducible on a simple scene; I've logged it (internal bug-tracker id: VGPU-5776) for developer investigation. Though tedious, for now, use the manual cache clearing method (restarting 3ds Max). I've already pinged the devs about the case.

[nicolas_fuminier]

Hello,

Thank you for the follow-up,
Happy to help.

At the same time we found a temporary workaround solution with Ornatrix Alembic import and understood why our scenes were crashing with this method previously (if someone struggle with this method I can explain our solution)
That said, the method with the VRAY proxy seems to be the most optimized and allowed us to render the hair in IPR (which was perfect for the shading/lighting phase).
We are looking forward to find this option available again in our pipeline.

Thanks again to the work of your team,
Have a nice day,
Nicolas

[MANUEL_MOUSIOL]

Hi Nicolas,
do you care to explain about your workaround?
We are trying to render ornatrix hair in GPU as well but I guess a proxy is the way to go since the option "view count from render" or rather render count under the dense hair settings doesnt seem to work for GPU.
We have indeed an animation going - is your solution workable with that?
Thanks in advance for any pointers!

Cheers,
Manuel

[nicolas_fuminier]

Hello MANUEL_MOUSIOL ,

I will try to help you, not knowing if my approach meets your needs.

At the beginning we had retained 3 possibles options to render Ornatrix hair on 3DSMAX VRAY GPU



1/ Directly with the native Ornatrix modifiers in the layout scene that will be used for rendering (img 001).
No particular technical disadvantage, the rendering of native Ornatrix modifiers seems to work perfectly well in VRAY GPU.
The main problem with this solution is that I can't "compile" the hair simulation. It remains in native 3DSMAX modifiers and these hairs must be present until the end of the production line with a risk of losing some Ornatrix specific settings (Guides from surfaces, Surface comb, etc.) following changes in the main scene. Not to mention the impossibility of working with several people and merging the work in a master scene.
This remains a viable solution in some cases, just very restrictive in terms of pipeline.



2/ Via the Ornatrix .abc export (Select the gromming mesh to export, 3SDMAX "file" > "export selected" > Ornatrix .abc) and an import in another master scene via a "Vray Proxy" in the geometry creation tab "VRAY".

Even if we did not push our tests in this direction this solution should work with an animated hairstyle.
Recommended solution on the different sources we have been able to consult.
The major problem is the one raised in my first post with a VRAM stacking bug making it impossible to use this method for a sequence of moving images.
For the moment this solution is unusable in VRAY GPU.



3/ Via the Ornatrix .abc export (Select the gromming mesh to export, 3SDMAX "file" > "export selected" > Ornatrix .abc) and an import in another master scene via 3SDMAX "file" > "import" > import Ornatrix .abc.
Do not import the Ornatrix .abc via the geometry creation tab "EPHERE Ornatrix" > Ornatrix "Ox Baked Hair" > Source Files "File Paths" > "File 1 : ..." (img 003_A).
Even if in the end we end up with an "Ox Baked Hair" in both cases, the first import solution seems to us much more stable than the second.

Even if we did not push our tests in this direction this solution should work with an animated hairstyle.
Solution that we had discarded at first because our layout scene crashed instantly without importing the hairstyle. We had hairstyles with too many polygons to display in the OPENGL viewer and the scene did not support this import.
The solution is to change the display mode in 3DSMAX (before importing the abc) from "Optimized mesh" to "Spline" and then reduce the number of hair to be displayed in the OPENGL viewer to the value you want depending on your computer characteristics and the complexity of your grooming.
3DSMAX > Ornatrix tab > about/setting dialog tab > settings. (img 003_B then img 003_C)
For security we have set a value of 1 in our pipe line. This manipulation must be done on ALL 3DSMAX involved in your pipeline, worksation, renderstation, otherwise they will not be able to open this scene without crashing.
This is the option we choose for the moment in our pipeline.



I hope to have answered, even partially, your question,
I remain available if you need more details,

I wish you beautiful images,
Nicolas

[hermit.crab]

Just so you know, the developers have begun fixing the issue.

[nicolas_fuminier]

hermit.crab

Thanks a lot for the feedback,
The third option is totally viable at this time, but more option is always better.

Kuddos to the team,
Best,
Nicolas