GPU Hair Rendering Bug - "Glitter" with particular Root to Tip sizes #67146

New Issue

Joe Williamsen · 2019-07-17T23:24:44+02:00

Joe Williamsen commented

2019-07-17 23:24:44 +02:00

System Information
Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: GeForce RTX 2070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.64

Blender Version
Broken: version: 2.80 (sub 74), branch: master, commit date: 2019-07-11 13:50, hash: 06312c6d2d
Worked: (optional)

Short description of error
In a perfect storm of GPU rendering + Hair with Radius Root size smaller or equal to the Tip size, bright white "cards" appear at the tips of some hair strands.
Switching to CPU rendering, the anomalies go away.

Also, making the Root size Large and the Tip size small reduces the cards, but they are still there.

Hair Render Bug.zip

Exact steps for others to reproduce the error

Open the attached file in Blender 2.80
Switch to the Camera view if not already there
Render (should be set to Cycles using GPU)
Switch to Cycles using CPU rendering
Render

Optionally:

Select the hair object (eyebrows)
Go to the particle tab
Under Hair Shape, change the Radius Root to, say, 0.45 and the Tip to 0.1
Render using GPU - cards are still there but are much smaller.

**System Information** Operating system: Windows-7-6.1.7601-SP1 64 Bits Graphics card: GeForce RTX 2070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.64 **Blender Version** Broken: version: 2.80 (sub 74), branch: master, commit date: 2019-07-11 13:50, hash: `06312c6d2d` Worked: (optional) **Short description of error** In a perfect storm of GPU rendering + Hair with Radius Root size smaller or equal to the Tip size, bright white "cards" appear at the tips of some hair strands. *Switching to CPU rendering, the anomalies go away.* Also, making the Root size Large and the Tip size small reduces the cards, but they are still there. ![cards.JPG](https://archive.blender.org/developer/F7615539/cards.JPG) ![Cpu no cards.JPG](https://archive.blender.org/developer/F7615542/Cpu_no_cards.JPG) [Hair Render Bug.zip](https://archive.blender.org/developer/F7615545/Hair_Render_Bug.zip) **Exact steps for others to reproduce the error** Open the attached file in Blender 2.80 Switch to the Camera view if not already there Render (should be set to *Cycles using GPU*) Switch to *Cycles using CPU* rendering Render Optionally: Select the hair object (eyebrows) Go to the particle tab Under Hair Shape, change the Radius Root to, say, 0.45 and the Tip to 0.1 Render using GPU - cards are still there but are much smaller.

blender-admin commented

2019-07-17 23:24:44 +02:00

#72033 was marked as duplicate of this issue

Joe Williamsen commented

2019-07-17 23:24:45 +02:00

Added subscriber: @Joe_W

Philipp Oeser commented

2019-07-18 11:12:49 +02:00

Added subscribers: @Sergey, @brecht, @lichtwerk

Philipp Oeser commented

2019-07-18 11:12:49 +02:00

Can confirm.
Interestingly, this happens on CPU for me as well (Intel® Core™ i7-6700 CPU @ 3.40GHz × 8).
Also, for me, changing Root Radius has no affect on the size of the "cards".

@brecht: mind checking? CC @Sergey

Can confirm. Interestingly, this happens on CPU for me as well (Intel® Core™ i7-6700 CPU @ 3.40GHz × 8). Also, for me, changing Root Radius has no affect on the size of the "cards". @brecht: mind checking? CC @Sergey

Brecht Van Lommel was assigned by Philipp Oeser

2019-07-18 11:13:07 +02:00

Germano Cavalcante commented

2019-11-29 14:34:11 +01:00

Added subscriber: @Tuz

Brecht Van Lommel was unassigned by Dalai Felinto

2019-12-23 16:33:42 +01:00

Thomas Dinges commented

2021-11-18 21:15:05 +01:00

Added subscriber: @ThomasDinges

Thomas Dinges commented

2021-11-18 21:15:05 +01:00

Changed status from 'Confirmed' to: 'Resolved'

Thomas Dinges closed this issue

2021-11-18 21:15:05 +01:00

Thomas Dinges self-assigned this 2021-11-18 21:15:05 +01:00

Thomas Dinges commented

2021-11-18 21:15:05 +01:00

I cannot reproduce the white boxes any more with Blender 3.0 Beta (CPU and HIP), so assume it's fixed on CUDA as well. https://builder.blender.org/download/daily/

Joe Williamsen commented

2021-11-18 22:30:21 +01:00

It actually looks like something is still happening there - but it's very dim now - like a ghost of its' former self - so I don't think it's a problem any more (hopefully)

Thanks for checking it out :)

It actually looks like something is still happening there - but it's very dim now - like a ghost of its' former self - so I don't think it's a problem any more (hopefully) ![Screenshot 2021-11-18 142727.jpg](https://archive.blender.org/developer/F11826369/Screenshot_2021-11-18_142727.jpg) Thanks for checking it out :)

Thomas Dinges commented

2021-11-18 22:44:56 +01:00

Changed status from 'Resolved' to: 'Confirmed'

Thomas Dinges reopened this issue

2021-11-18 22:44:56 +01:00

Thomas Dinges commented

2021-11-18 22:44:56 +01:00

Hm indeed, re-opening then. Thanks for testing!

Thomas Dinges removed their assignment 2021-11-23 11:43:52 +01:00

Philipp Oeser removed the

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GPU Hair Rendering Bug - "Glitter" with particular Root to Tip sizes #67146