I imported a pretty heavy vdb fire simulation from Embergen (200 - 600 MB per frame) and I’m rendering it out in Blender.
I can render each individual frame just fine, but I can’t render more than 40 frames in a row before getting the error: System is out of GPU and shared host memory. I checked my VRAM, and it was ok, but my RAM was filling up. Blender would reach about 55 GB of my 64 GB of ram, then stop rendering. I could just start rendering the animation again from where it stopped, but this is a painful and slow process, especially for my 500 frame animation. Any ideas for a workaround or solution?
The result was stable memory usage and no problem.
We used blender 3.6.5 and blender 4.1.0 for this test, and we saw a positive memory reduction in blender 4.1.0. (blender 3.6.5 VRAM 2gb, blender 4.1.0 VRAM 1.2gb)
Try another version of the blender and update the graphics card driver.
If you’re using multiple VDBs, look for objects that cause problems.
Next step would be to run Blender through a debugger like gdb and make full backtrace if you can make Blender to crash. I did try that, but unfortunately haven’t found anything useful.
Lastly you can try to ask the developers if tools like ASAN can pick up leaks from OpenVDB and if this could be helpful.
