Density of volume shader doesn't change/react on input value #96795

New Issue

Christoph Duyster · 2022-03-26T11:00:32+01:00

Christoph Duyster commented

2022-03-26 11:00:32 +01:00

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: f1cca30557
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.blend

**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: `f1cca30557` 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. ![image.png](https://archive.blender.org/developer/F12948040/image.png) 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: ![image.png](https://archive.blender.org/developer/F12948034/image.png) 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... ![image.png](https://archive.blender.org/developer/F12948037/image.png) [density_by_distance.blend](https://archive.blender.org/developer/F12948030/density_by_distance.blend)

Christoph Duyster commented

2022-03-26 11:00:32 +01:00

Added subscriber: @LuckyChris

blender-admin commented

2022-03-26 11:00:32 +01:00

#96521 was marked as duplicate of this issue

Pratik Borhade commented

2022-03-28 07:59:46 +02:00

Added subscriber: @PratikPB2123

Philipp Oeser commented

2022-03-28 10:41:40 +02:00

Added subscribers: @brecht, @lichtwerk

Philipp Oeser commented

2022-03-28 10:41:40 +02:00

Changed status from 'Needs Triage' to: 'Needs Developer To Reproduce'

Philipp Oeser commented

2022-03-28 10:41:40 +02:00

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: correct me if I am wrong).

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: correct me if I am wrong).

Brecht Van Lommel commented

2022-03-29 19:55:05 +02:00

Changed status from 'Needs Developer To Reproduce' to: 'Archived'

Brecht Van Lommel closed this issue

2022-03-29 19:55:05 +02:00

Brecht Van Lommel commented

2022-03-29 19:55:05 +02:00

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 commented

2022-03-30 16:27:01 +02:00

Added subscriber: @Mantissa

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Density of volume shader doesn't change/react on input value #96795