Tips on Rendering VDB Volumes with Volume Grid shader QUICKLY!

[sv]

Hi All,

I have a simple test scene setup where I'm instancing some cloud VDB's around on a grid (via 'copy_to_points') to make some cloudscapes.
The VDB's have a Volume Grid shader applied, and are rendering correctly - however I've noticed that I don't seem to be able to use really low sampling settings on the Image Sampler to achieve _very fast and noisy quick test renders_.
Even with Min & Max Samples = 1, and the AA Noise Threshold at 0.5, I am still getting 'clean' renders; yet they are much slower than I want to be working - i.e. I'm looking at rendertimes around half an hour+, whereas I'm trying to churn out super noisy frames which finish in a couple of minutes so I can iterate quickly....
Any tips - it's like the Volume Grid shader seems decoupled from the AA Image Sampler - I'm sure it's not; I'm sure there is a setting somewhere I'm overlooking but I don't know what it is....

Vray 5 for Houdini...

Any help most appreciated.

[hsz]

where you gonna see the difference in speed is on the shader itself, play with the sampling go higher if you want to get quicker result.

https://docs.chaosgroup.com/display/.../Rendering+tab

Also, if you use the GPU is way faster than the CPU to get results with volumes in general.

[doppelgaengerdigital]

I can only speak for maya, but I think you have to switch to ray-traced light scattering.
if this doesn't work try disabling light cache. Can't check myself right now. But I believe it's one of the two settings

[tsvetomira.girginova]

Dear sv, hello. Please observe that the following is done:

1. Volume Light Cache must be OFF
2. Light Scattering Type must be set to Ray-Traced
3. Optimize Big Volumetric Grids must be OFF

Best regards,
TS