VRay not-Responding when rendering skatter objects

[mandy_lam]

Created skatter render only objects in my model. But VR is non-responding when I tried to render. Has to kill the SU process manually.
This is first time I use skatter so I don't know if this is an issue with other SU/VR versions or just my file.
Am using SU Pro version 21.1.279; VR 5.10.05 and Skatter V1.4.21 on Windows 10 w/ 64GB memory.
I've provided link to problem file.
thanks.

[Peter.Chaushev]

Hello, Mandy,
Thank you for providing the scene!
It appears that the Skatter instances are too numerous and take up too much of your machine's memory.
If you wait enough time a "[V-Ray] Exception in CORE: Memory allocation failure" error appears eventually. The required memory for that skatter setup is ~97GB.

There are several solution you can choose to apply (or combine together):

• Decrease the density of the Skatter instances
• Use a lighter grass model (one with less faces and thus occupying less memory)
• Decrease the area of the of distribution
• Enable the 'Exclude non-visible' Skatter option

or alternatively:

• Substitute the Skatter grass with V-Ray Fur (and have its level of detail option enabled)

You can adjust the solution based on the memory usage reported in the V-Ray progress window or the "Stats" tab of the right-side VFB panel.
Let me know if this helps!

Kind regards,
Peter

[mandy_lam]

Peter,
Thanks for looking into my file. I tried to change to lower density (0.03) and enable 'Exclude non-visible' Skatter option, also switch to use CPU instead of CUDA for rendering. The first time works and Ram usage shown in VFB stats was only about 15% of total available memory (64GB). But the grass density is too low that the result is not acceptable. I then increase density back to 0.1, same not responding issue happens. My memory usages while SU/VR hangs are below. It looks like there are still plenty of free memory to use? I am not able to access VFB stats since VR hangs.
Glad to know VR Fur is an option. I just want to understand why Skatter fails while there seems to have plenty of memory available.