Cycles: No Hair Shadows with Transparent BSDF #94136

New Issue

Chris Jones · 2021-12-16T04:17:29+01:00

Chris Jones commented

2021-12-16 04:17:29 +01:00

System Information
Operating system: Windows-10-10.0.19043-SP0 64 Bits
Graphics card: GeForce 9600 GT/PCIe/SSE2 NVIDIA Corporation 3.3.0

Blender Version
Broken: version: 3.1.0 Alpha, branch: master, commit date: 2021-12-14 21:50, hash: 644eb68524
Worked: versions prior to 3.0

Short description of error
Hair particles fail to render shadows in Cycles when a Transparent BSDF node is used, despite the shadows being present when rendering in the viewport.

Exact steps for others to reproduce the error

Load example file Transparent Hair Shadows.blend
Render scene in viewport; note that shadows are present (there is a repeated pattern in the shadows which may be related, but has been reported separately: https://developer.blender.org/T94135).
F12 render and note absence of shadows
Connect Principled Hair BSDF directly to Material Output for shadows to appear in render

A use case for transparent hair is to dissolve the hair root with a gradient to soften the hard edge, creating the impression of it being embedded in translucent skin.

**System Information** Operating system: Windows-10-10.0.19043-SP0 64 Bits Graphics card: GeForce 9600 GT/PCIe/SSE2 NVIDIA Corporation 3.3.0 **Blender Version** Broken: version: 3.1.0 Alpha, branch: master, commit date: 2021-12-14 21:50, hash: `644eb68524` Worked: versions prior to 3.0 **Short description of error** Hair particles fail to render shadows in Cycles when a Transparent BSDF node is used, despite the shadows being present when rendering in the viewport. **Exact steps for others to reproduce the error** - Load example file [Transparent Hair Shadows.blend](https://archive.blender.org/developer/F12751765/Transparent_Hair_Shadows.blend) - Render scene in viewport; note that shadows are present (there is a repeated pattern in the shadows which may be related, but has been reported separately: https://developer.blender.org/T94135). - F12 render and note absence of shadows - Connect Principled Hair BSDF directly to Material Output for shadows to appear in render A use case for transparent hair is to dissolve the hair root with a gradient to soften the hard edge, creating the impression of it being embedded in translucent skin.

Chris Jones commented

2021-12-16 04:17:29 +01:00

Added subscriber: @ChrisJones

Alaska commented

2021-12-16 07:20:50 +01:00

Added subscribers: @brecht, @Alaska

Alaska commented

2021-12-16 07:20:50 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Alaska commented

2021-12-16 07:20:50 +01:00

Can confirm in: 3.1.0 Alpha, branch: master, commit date: 2021-12-16 05:27, hash: 8dbd406ea0

CC @brecht as you worked on transparent baking for hair and this issue seems to be related to that based on my bisecting fd77a28031

Can confirm in: 3.1.0 Alpha, branch: master, commit date: 2021-12-16 05:27, hash: `8dbd406ea0` CC @brecht as you worked on transparent baking for hair and this issue seems to be related to that based on my bisecting fd77a28031

Dylan Lobbregt commented

2022-07-31 03:04:58 +02:00

Added subscriber: @DylanLobbregt