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Maniphest T70811

2.81 eevee - Alpha clip/Alpha hashed causes visual glitches when exporting PNG with Alpha
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Description

System Information
Operating system: Windows-10-10.0.14393 64 Bits
Graphics card: GeForce GTX 1050 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 431.86

Blender Version
Broken: version: 2.81 (sub 15), branch: master, commit date: 2019-10-12 15:33, hash: rB95f020c853d6
Worked: version: 2.81 (sub 14), branch: master, commit date: 2019-10-09 07:42, hash: rB40a55be82cf5

Short description of error
When geometry that has transparency with either Alpha clip or Alpha hashed, intersects other objects, the intersection borders create these black dots that only appear when file is exported with RGBA
This only happens in EEVEE, this problem does not occur in cycles

Exact steps for others to reproduce the error
-default blender file (eevee)
-duplicate cube and shift it to side so that both intersect
-change second cube's material alpha value to 0, and set blend and shadow mode to alpha clip/alpha hashed
-Render (you should notice that only first cube appears in image viewer w/o any apparent problem)
-Save image as > PNG with RGBA
-Open that image and notice that there are visual artifacts where both objects should be intersecting

ps:This effect is even more apparent if there's camera motion blur present

untitled.blend592 KBDownload

Revisions and Commits

rB Blender
rB4142f3993cd8 Fix T70811 EEVEE: Alpha clip/hashed cause wrong alpha values

Event Timeline

Vas (Alumx) created this task.Oct 14 2019, 4:12 PM
Vas (Alumx) edited projects, added BF Blender (2.81), Eevee; removed BF Blender.
Jacques Lucke (JacquesLucke) lowered the priority of this task from 90 to 50.Oct 14 2019, 4:27 PM
Jacques Lucke (JacquesLucke) edited projects, added BF Blender; removed BF Blender (2.81).
Jacques Lucke (JacquesLucke) added subscribers: Clément Foucault (fclem), Jacques Lucke (JacquesLucke).

I can reproduce it I think. It would be helpful if you could provide the simple .blend file. Just to make sure we are testing using the same scene.

Vas (Alumx) updated the task description. (Show Details)Oct 14 2019, 4:32 PM

@Jacques Lucke (JacquesLucke) There ya go! I updated the task with .blend file included

Jacques Lucke (JacquesLucke) assigned this task to Clément Foucault (fclem).Oct 14 2019, 4:42 PM

thanks.

Clément Foucault (fclem) raised the priority of this task from 50 to High.Oct 16 2019, 9:25 PM
Clément Foucault (fclem) changed the task status from Unknown Status to Resolved by committing rB4142f3993cd8: Fix T70811 EEVEE: Alpha clip/hashed cause wrong alpha values.Oct 17 2019, 5:41 PM
Clément Foucault (fclem) added a commit: rB4142f3993cd8: Fix T70811 EEVEE: Alpha clip/hashed cause wrong alpha values.
Clément Foucault (fclem) edited projects, added EEVEE & Viewport; removed Eevee.Jun 19 2020, 10:05 PM