MNEE Caustics ray depth is incorrect #97921

New Issue

Alaska · 2022-05-07T03:42:29+02:00

Alaska commented

2022-05-07 03:42:29 +02:00

System Information
Operating system: Linux-5.17.0-1-amd64-x86_64-with-glibc2.33 64 Bits
Graphics card: NVIDIA GeForce RTX 3060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 510.68.02

Blender Version
Broken: version: 3.3.0 Alpha, branch: master, commit date: 2022-05-06 21:48, hash: 98a04ed452
Worked: NA as this issue is present in all Blender versions with MNEE Caustics

Short description of error
The ray depth for MNEE Caustics is incorrect. This results in noticeable differences when enabling MNEE caustics in a scene where the ray depth is used to influence the final render.

Example render:
In this scene there is a sphere that's casting caustics both inside it and behind it on a plane (Note: The is invisible to the camera). I have used ray depth to change the colour of the light source upon passing through the sphere. You can find the .blend file I used attached at the end of this report.


Rendered without MNEE	Rendered with MNEE

Exact steps for others to reproduce the error

Change the render engine to Cycles.
Setup a scene for MNEE caustics by adding a caustic caster, caustic receiver, shadow caustic light, etc.
Use one of the Depth outputs on a light path node to adjust the colour and/or brightness of the caustics. (I have included an image of an example node setup for the shadow caustic light)
Notice how MNEE caustics and non MNEE caustics produce different results as if the caustics have a different ray depth between the two techniques. This can be done by enabling and disabling MNEE caustics and comparing the results.

Example node setup for light:

Here is a .blend file with steps 1-3 done for you.
#97921 - MNEE Caustics ray depth issue.blend

**System Information** Operating system: Linux-5.17.0-1-amd64-x86_64-with-glibc2.33 64 Bits Graphics card: NVIDIA GeForce RTX 3060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 510.68.02 **Blender Version** Broken: version: 3.3.0 Alpha, branch: master, commit date: 2022-05-06 21:48, hash: `98a04ed452` Worked: NA as this issue is present in all Blender versions with MNEE Caustics **Short description of error** The ray depth for MNEE Caustics is incorrect. This results in noticeable differences when enabling MNEE caustics in a scene where the ray depth is used to influence the final render. Example render: In this scene there is a sphere that's casting caustics both inside it and behind it on a plane (Note: The is invisible to the camera). I have used ray depth to change the colour of the light source upon passing through the sphere. You can find the .blend file I used attached at the end of this report. |![Ray depth no MNEE caustic test.jpg](https://archive.blender.org/developer/F13055602/Ray_depth_no_MNEE_caustic_test.jpg)|![Ray depth MNEE caustic test.jpg](https://archive.blender.org/developer/F13055604/Ray_depth_MNEE_caustic_test.jpg)| | -- | -- | |Rendered without MNEE|Rendered with MNEE| **Exact steps for others to reproduce the error** 1. Change the render engine to Cycles. 2. Setup a scene for MNEE caustics by adding a caustic caster, caustic receiver, shadow caustic light, etc. 3. Use one of the `Depth` outputs on a light path node to adjust the colour and/or brightness of the caustics. (I have included an image of an example node setup for the shadow caustic light) 4. Notice how MNEE caustics and non MNEE caustics produce different results as if the caustics have a different ray depth between the two techniques. This can be done by enabling and disabling MNEE caustics and comparing the results. Example node setup for light: ![Ray depth MNEE caustic node setup.png](https://archive.blender.org/developer/F13055600/Ray_depth_MNEE_caustic_node_setup.png) Here is a .blend file with steps 1-3 done for you. [#97921 - MNEE Caustics ray depth issue.blend](https://archive.blender.org/developer/F13055606/T97921_-_MNEE_Caustics_ray_depth_issue.blend)

Alaska commented

2022-05-07 03:42:29 +02:00

Added subscriber: @Alaska

Pratik Borhade commented

2022-05-09 04:13:35 +02:00

Added subscribers: @olivier.fx, @PratikPB2123

Pratik Borhade commented

2022-05-09 04:13:35 +02:00

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

Pratik Borhade commented

2022-05-09 04:13:35 +02:00

cc @olivier.fx

Philipp Oeser commented

2022-05-09 14:17:07 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2022-05-09 14:17:07 +02:00

Following the "bug in new feature" policy, will set to High priority.

Olivier Maury commented

2022-05-10 05:03:47 +02:00

Thanks for creating this scene @Alaska, it surfaced 2 issues which D14902 should hopefully address:

transmission depth was not computed correctly.
bounce info was not updated appropriately when evaluating related shader graphs.

With the patch applied, the scene above renders like this:

With the hemisphere camera visibility enabled:

Thanks for creating this scene @Alaska, it surfaced 2 issues which [D14902](https://archive.blender.org/developer/D14902) should hopefully address: - transmission depth was not computed correctly. - bounce info was not updated appropriately when evaluating related shader graphs. With the patch applied, the scene above renders like this: ![image.png](https://archive.blender.org/developer/F13063157/image.png) With the hemisphere camera visibility enabled: ![image.png](https://archive.blender.org/developer/F13063160/image.png)

blender-admin commented

2022-05-17 20:16:52 +02:00

This issue was referenced by b48adbc9d7

This issue was referenced by b48adbc9d79c55b8dac368865098b34c7536d74f

Brecht Van Lommel commented

2022-05-17 21:08:47 +02:00

Changed status from 'Confirmed' to: 'Resolved'

Brecht Van Lommel closed this issue

2022-05-17 21:08:47 +02:00

Brecht Van Lommel self-assigned this 2022-05-17 21:08:47 +02:00

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MNEE Caustics ray depth is incorrect #97921