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Adaptive sampling breaks value Shader AOV's
Closed, ResolvedPublicBUG


System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 1060 3GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 442.19

Blender Version
Broken: version: 2.83 (sub 6), branch: master, commit date: 2020-03-06 22:46, hash: rBdcdcc2348842
Worked: (optional)

Short description of error
Value shader AOV's are broken after enabling adaptive sampling.
The Images are showing a simple noise texture plugged into the Value slot of an AOV output.

Expected result (no adaptive sampling):

Adaptive Sampling GPU only:

Adaptive Sampling CPU only:

Adaptive Sampling CPU+GPU:

Using a realy low adaptive threshold fixes the problem but it basically eliminates the purpose of AS.

Plugging the texture into the Color slot and setting the AOV also to color fixes the Problem.

Exact steps for others to reproduce the error

  • create a noise texture node in the Material of the default cube
  • plug it into a AOV output node as a Value
  • create a new Shader AOV pass referencing the AOV node and setting it to value
  • enable Adaptive sampling
  • render: the AOV pass is broken
  • plug the texture into the color slot and set the AOV pass to color
  • render: the resulting pass is as expected
  • disableing adaptive sampling also fixes the problem

Event Timeline

J-P Busse (Corefrecs) renamed this task from Adaptive sampling breaks Shader AOV to Adaptive sampling breaks value Shader AOV's.Mon, Mar 9, 12:21 PM
J-P Busse (Corefrecs) created this task.

I just noticed that the AOV pass gets somehow the sample count pass as an Alpha chanel which makes the AOV pass basically unusable for compositing, I don't realy know whats going on here. Just view the AOV pass as Color and alpha or with a viewer node in the compositor. I had no luck recovering the pass so far.

By the way CPU+GPU rendering seems to be broken with adaptive sampling.
This is the Sample Count pass:

Philipp Oeser (lichtwerk) changed the task status from Needs Triage to Confirmed.Tue, Mar 10, 3:24 PM
Philipp Oeser (lichtwerk) changed the subtype of this task from "Report" to "Bug".
Brecht Van Lommel (brecht) triaged this task as High priority.Fri, Mar 20, 2:05 PM

In my case Adaptive Sampling adds noisy dilatated (3x3px) shading mixed into AOV (both color and value).
Expected solid white mask:

It looks like the issue is that AOV Values aren't being normalised to the actual sample count but to the max samples. a workaround is to divide the AOV value by the debug sample count value in the compositor (see attached files)