Volume shader not working right with geometry nodes and curves #109279

New Issue

SteveLogue · 2023-06-23T11:32:40+02:00

SteveLogue commented

2023-06-23 11:32:40 +02:00

System Information
Operating system: Windows-10-10.0.18363-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 2080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 536.23

Blender Version
Broken: version: 3.5.1, branch: blender-v3.5-release, commit date: 2023-04-24 18:11, hash: e1ccd9d4a1d3
Worked: I tried this in 3.4 and it worked, I haven't tried further back

Short description of error

I have a cube with a volume shader with emission glow - works fine.

I use geometry nodes to add some more mesh to this (e.g. icosphere) and set the material to a volume shader, works fine.

I use geometry nodes to add a spiral curve and a bezier circle to create a spiral mesh and set a volume shader material and it doesn't work correctly.

The shader only works if there's another object behind. If there's nothing behind the spiral then it's just not rendered (transparent). But any part of the spiral that overlaps another object, or even another part of the spiral, gets rendered correctly.

Exact steps for others to reproduce the error

Open the attached blend file and switch to rendered preview mode. You'll see a cube with a red volume shader using red emission light. Works fine.

You'll see an icosphere as part of the same object. This was added in geometry nodes and uses a green volume shader. This also works fine.

You'll also see a blue spiral. This was added using geometry nodes (spiral primitive + bezier circle -> mesh -> set material) but this is not rendered correctly. If you rotate the view, you'll see it only gets rendered where it overlaps something else.

If I use a surface shader for the spiral, it works OK so it's just the volume shader that's causing the problem.

**System Information** Operating system: Windows-10-10.0.18363-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 2080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 536.23 **Blender Version** Broken: version: 3.5.1, branch: blender-v3.5-release, commit date: 2023-04-24 18:11, hash: `e1ccd9d4a1d3` Worked: I tried this in 3.4 and it worked, I haven't tried further back **Short description of error** I have a cube with a volume shader with emission glow - works fine. I use geometry nodes to add some more mesh to this (e.g. icosphere) and set the material to a volume shader, works fine. I use geometry nodes to add a spiral curve and a bezier circle to create a spiral mesh and set a volume shader material and it doesn't work correctly. The shader only works if there's another object behind. If there's nothing behind the spiral then it's just not rendered (transparent). But any part of the spiral that overlaps another object, or even another part of the spiral, gets rendered correctly. **Exact steps for others to reproduce the error** Open the attached blend file and switch to rendered preview mode. You'll see a cube with a red volume shader using red emission light. Works fine. You'll see an icosphere as part of the same object. This was added in geometry nodes and uses a green volume shader. This also works fine. You'll also see a blue spiral. This was added using geometry nodes (spiral primitive + bezier circle -> mesh -> set material) but this is not rendered correctly. If you rotate the view, you'll see it only gets rendered where it overlaps something else. If I use a surface shader for the spiral, it works OK so it's just the volume shader that's causing the problem.

BlenderBugReport.blend

978 KiB

SteveLogue added the

labels 2023-06-23 11:32:40 +02:00

Iliya Katushenock commented

2023-06-23 12:38:22 +02:00