Maniphest T83170

Smoke render on CPU is different from GPU (CPU appears to have better quality)
Closed, Duplicate
Actions

Assigned To
None
Authored By
Valeri Barashkov (valera)
Nov 29 2020, 1:26 AM
Tags
  • BF Blender
Subscribers
Alaska (Alaska)
Valeri Barashkov (valera)

Description

System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 457.30

Blender Version
Broken: version: 2.91.0, branch: master, commit date: 2020-11-25 08:34, hash: rB0f45cab862b8
Worked: (newest version of Blender that worked as expected)

Short description of error
Render results are different in attached blend file when switching from CPU to GPU.

Exact steps for others to reproduce the error
Select Domain object and reduce resolution unless you don't mind waiting.
Bake smoke.
Select last frame.
Render on CPU and then on GPU.
Compare the two render results.

Additional info: It appears that Denoising is also different (tested with OpenImageDenoise).

wf.blend1004 KBDownload

Event Timeline

Valeri Barashkov (valera) created this task.Nov 29 2020, 1:26 AM
Alaska (Alaska) added a subscriber: Alaska (Alaska).Nov 29 2020, 4:01 AM

The cause from my understanding is due to the CPU supporting decoupled volume sampling while the GPU does not. To work around this, you must select the domain, and change the volume sampling method to Distance. This disables decoupled volume sampling on the CPU giving consistent results between the GPU and CPU.

Alaska (Alaska) closed this task as a duplicate of T54577: Cycles smoke render differs on CPU from GPU.Nov 29 2020, 4:01 AM