Maniphest T97736

Transparent objects are visible inside volumetric materials (Cycles)
Closed, Duplicate
Actions

Assigned To
None
Authored By
Rincewind (Rincewind3D)
Apr 30 2022, 3:06 PM
Tags
  • BF Blender
Subscribers
Pratik Borhade (PratikPB2123)
Rincewind (Rincewind3D)

Description

System Information
Operating system: Windows-10-10.0.19042-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 2080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 512.15

Blender Version
Broken: version: 3.1.2, branch: master, commit date: 2022-03-31 17:40, hash: rBcc66d1020c3b
Worked: (newest version of Blender that worked as expected)

Short description of error
In Blender 2.81 was a bug introduced which broke objects with an alpha inside a volume. This bug is already fixed for Evee, but the same bug still appears for Cycles:
https://developer.blender.org/T71402

Exact steps for others to reproduce the error

  1. Create a plane with an alpha (in this case a cirlce):

  1. Create a volumne and a light

  1. Render the scene and you will get something like this:

(the alpha of the plane is broken)

Expected result is this (done with view layers in Cycles)

Example Blend file

bug cycles volume alpha.blend960 KBDownload

Related Objects

Event Timeline

Rincewind (Rincewind3D) created this task.Apr 30 2022, 3:06 PM
Rincewind (Rincewind3D) updated the task description.Apr 30 2022, 3:09 PM
Pratik Borhade (PratikPB2123) added a subscriber: Pratik Borhade (PratikPB2123).May 2 2022, 2:17 PM
Pratik Borhade (PratikPB2123) changed the task status from Needs Triage to Needs Information from User.May 2 2022, 2:40 PM

Hi, thanks for the report.
I suspect this is happening because of overlapping (plane & cube) faces: T96475: Overlapping geometry shows black faces on Cycles Blender 3.1 (Ray Tracing Precision)
Can you confirm if that's the case for you
Are you able to reproduce this in previous versions?(2.93, 3.0.0): https://www.blender.org/download/releases/3-0/

3.1 build older than rB74afc86d4bf13.1, 3.2
Rincewind (Rincewind3D) added a comment.May 2 2022, 4:11 PM

@Pratik Borhade (PratikPB2123)

Yes, it happens because over intersection between the volumne and the mesh.

Seems to be an duplicate of https://developer.blender.org/T96475

I can confirm that it is fixed in 3.2 alpha

Pratik Borhade (PratikPB2123) added a comment.May 2 2022, 7:24 PM

Hi, thanks for the update.
I'm closing this as duplicate. Thanks again for the report :)

Pratik Borhade (PratikPB2123) closed this task as a duplicate of T96475: Overlapping geometry shows black faces on Cycles Blender 3.1 (Ray Tracing Precision).May 2 2022, 7:24 PM