Volume equiangular sampling too noisy
Open, ConfirmedPublic

Description

The final result of a smoke render differs if using GPU (NVIDIA 1050 Ti) or using CPU (AMD 1300X).

CPU render - Volume sampling 0.1 - Volume bounces: 0
https://i.stack.imgur.com/2dg9h.png

CUDA render - Volume sampling 0.1 - Volume bounces: 0
https://i.stack.imgur.com/nB7qw.png

Having tests I found it out that it is something related to the volume sampling. Decreasing the value solves partially the problem for the CPU so it becomes nearly the one obtained with the GPU but... there still are enormous differences.

No settings have been touched from render to render.

CPU render - Volume sampling 0.01 - Volume bounces: 15
https://i.stack.imgur.com/a7CIF.jpg

CUDA render - Volume sampling 0.01 - Volume bounces: 15
https://i.stack.imgur.com/h2tYZ.jpg

BLENDER VERSIONS TESTED:

ARCH LINUX:
17:2.79.b.git3.32432d91-1 from the arch's repository.
2.79b official
2.79-c9608047472 experimental official
2.80-405c6c077f6 experimental official

in the 2.8 I can't bake so can't actually test... Is maybe the smoke simulation still under development?

BLEND FILE ATTACHED:

Details

Type
Bug

modified in order to not include the mentioned task but it remains mentioned, sorry about that ^^"

Brecht Van Lommel (brecht) triaged this task as Confirmed priority.

Only the CPU supports equiangular and multiple importance volume sampling, and that's where the issue seems to be. Workaround is changing the volume sampling to distance in the material properties settings panel.

Brecht Van Lommel (brecht) renamed this task from CPU render result differs from CUDA's one on smoke to Volume equiangular sampling too noisy.Thu, Jul 5, 11:24 AM