Maniphest T96795

Density of volume shader doesn't change/react on input value
Closed, Archived
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Assigned To
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Authored By
Christoph Duyster (LuckyChris)
Mar 26 2022, 11:00 AM
Tags
  • BF Blender
  • Render & Cycles
Subscribers
Brecht Van Lommel (brecht)
Christoph Duyster (LuckyChris)
Midge Sinnaeve (mantissa)
Philipp Oeser (lichtwerk)
Pratik Borhade (PratikPB2123)

Description

System Information
Operating system: macOS-12.1-arm64-arm-64bit 64 Bits
Graphics card: Apple M1 Max Apple 4.1 Metal - 76.3

Blender Version
Broken: version: 3.0.0, branch: master, commit date: 2021-12-02 18:35, hash: rBf1cca3055776
Worked: (newest version of Blender that worked as expected)

Short description of error
[Please fill out a short description of the error here]

Exact steps for others to reproduce the error
[Please describe the exact steps needed to reproduce the issue]
[Based on the default startup or an attached .blend file (as simple as possible)]

I try to change the density of my volume shader based on the distance of 2 objects.

So i have this GN node tree, which obviously works because the distance value is coming over as you can see if i plugin my shader:

But if i want to see my volume shader....it looks like a constant value. So maybe i am making a stupid mistake or it is a bug...


density_by_distance.blend1 MBDownload

Related Objects

Mentioned In
T96521: Volume shading incorrect when using Random per Island node, UV's or Vertex Colors
Mentioned Here
M1: Bevel Tool Toolbar Layout - Multiple Overflow Popovers

Event Timeline

Christoph Duyster (LuckyChris) created this task.Mar 26 2022, 11:00 AM
Pratik Borhade (PratikPB2123) updated the task description.Mar 28 2022, 7:59 AM
Pratik Borhade (PratikPB2123) added a subscriber: Pratik Borhade (PratikPB2123).
Philipp Oeser (lichtwerk) changed the task status from Needs Triage to Needs Information from Developers.Mar 28 2022, 10:41 AM
Philipp Oeser (lichtwerk) added a project: Render & Cycles.
Philipp Oeser (lichtwerk) added subscribers: Brecht Van Lommel (brecht), Philipp Oeser (lichtwerk).

You cant use face/vertex based information in a volume shader, can you?
The distance in a shader works if you are rendering this on the surface, yes, but not so if done in a volume.
Dont think this has anything to do with the fact this is coming from geometry nodes, same is true for regular textures or vertex colors.

I think this can be closed (@Brecht Van Lommel (brecht): correct me if I am wrong).

Brecht Van Lommel (brecht) closed this task as Archived.EditedMar 29 2022, 7:55 PM

This is a limitation, there is no way to interpolate surface attributes into the volume. In the future there may be geometry nodes that help with that kind of thing, doing it at render time would be expensive.

Philipp Oeser (lichtwerk) mentioned this in T96521: Volume shading incorrect when using Random per Island node, UV's or Vertex Colors.Mar 30 2022, 4:26 PM
Philipp Oeser (lichtwerk) merged a task: T96521: Volume shading incorrect when using Random per Island node, UV's or Vertex Colors.
Philipp Oeser (lichtwerk) added a subscriber: Midge Sinnaeve (mantissa).