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Blender 2.9 external renderer shader node bug
Needs Information from User, NormalPublic

Description

System Information
Operating system: windows 10 64 bit
Graphics card: RTX 2060 super

Blender Version
Broken: Blender 2.90 official / but it happen since a while now with older blender version
Worked: reported once here : https://developer.blender.org/T76381

Short description of error

Blender doesn't save animation keyframe input (color/Value ...) in shader node with luxcore render engine.
From the blendluxcore Devs it is a blender issue.

Exact steps for others to reproduce the error

1/ install luxcore render engine from here : https://luxcorerender.org/download/

2/ in blender switch to Luxcore engine

3/ add a shader matte (or any shader)

4/ animate any shader value of your choice.

Event Timeline

Nandeya charles (sharlybg) renamed this task from Blender 2.8 external renderer shader node bug to Blender 2.9 external renderer shader node bug .Mon, Sep 14, 6:45 PM
Nandeya charles (sharlybg) created this task.

This is kind of super important for any third party render engine

Richard Antalik (ISS) changed the task status from Needs Triage to Confirmed.Wed, Sep 16, 5:34 PM

I can confirm, that preview is not updated when scrubbing timeline, Render is updated.

@Nandeya charles (sharlybg) do you have link to ticket in luxcore bugtracker?

As it is a blender bug i didn't open a bug issue on Luxcore bug tracker. But just in cases it is needed here is the link to the BlendLuxcore bug tracker : blendluxcore bug tracker

Richard Antalik (ISS) changed the task status from Confirmed to Needs Information from User.Thu, Sep 17, 2:55 PM

As it is a blender bug i didn't open a bug issue on Luxcore bug tracker. But just in cases it is needed here is the link to the BlendLuxcore bug tracker : blendluxcore bug tracker

You said "From the blendluxcore Devs it is a blender issue." So I assumed you reported this and they said it's bug in Blender, I also confirmed this on that basis. It would definitely help if we knew why this is bugh in Blender.

Since I have not triaged this really, we need to have another look. But to triage this issue we need example file that demonstrates the bug. I would assume that the node or tree is not doing something sometimes, but I need to know that exactly. Having example file is best because both of us can test if things are working correctly.

Sorry if I misunderstand something.

Sorry for late reply. Here is the file :

Tried the file in Blender 2.83LTS + Blendluxcore 2.4 official and it work. But Blender 2.83LTS + Blendluxcore 2.5 don't.
will test blender 2.9 official + 2.5 and 2.4 blendluxcore.

Thanks for example file, but that is not quite what I meant. This would require us to work not only with Blendr code, but also with Luxcore's. We should not need to use Luxcore to demonstrate this bug if it is bug in Blender.

Tested with Blender 2.9 + Blendluxcore 2.4 and it work.

@Simon Wendsche (BYOB) Hi, I don't know if you know about this issue, but since you are Luxcore dev can you share some information that can help us track and fix this?

With Blender 2.9 and latest BlendLuxCore v2.5 I can not reproduce the problem.

Blender 2.9 and latest BlendLuxCore v2.5 same issue with two files :

and this one

You should include a description what the actual bug is.
I thought the problem was that keyframes can't be set on properties of custom nodes, or don't show up in the UI.

However, the actual problem is that keyframes on custom node properties are either not evaluated or not updated when doing a final render of the full animation with Ctrl+F12. Rendering individual frames with F12 works as expected, and the keyframes show up in the UI as yellow/green on the node properties.

I can reproduce the issue with Blender 2.9 and BlendLuxCore v2.5 (have not tested other versions of either).

I have put together a minimal script to show the issue without requiring the installation of the BlendLuxCore addon:

  • Open scene in Blender 2.9
  • Press "run script" in the text editor on the left
  • Hover the mouse over the float property of the node on the right, and set a keyframe with I
  • Advance 10 frames, change the value (e.g. to 20) and set another keyframe
  • Go back to frame 1, and again advance 10 frames. Check the console, it will show an output like this:
frame: 1
my_float_prop: 1.0
---
frame: 2
my_float_prop: 1.6515774726867676
---
frame: 3
my_float_prop: 3.3978052139282227
---
frame: 4
my_float_prop: 5.925926208496094
---
frame: 5
my_float_prop: 8.923182487487793
---
frame: 6
my_float_prop: 12.076818466186523
---
frame: 7
my_float_prop: 15.074075698852539
---
frame: 8
my_float_prop: 17.602191925048828
---
frame: 9
my_float_prop: 19.34842300415039
---
frame: 10
my_float_prop: 20.0
---
  • Render with Ctrl+F12
  • Check the console again, it will show an output like this:
Saved: 'C:\tmp\0001.png'
 Time: 00:00.41 (Saving: 00:00.00)

frame: 2
my_float_prop: 20.0
---
Saved: 'C:\tmp\0002.png'
 Time: 00:00.01 (Saving: 00:00.00)

frame: 3
my_float_prop: 20.0
---
Saved: 'C:\tmp\0003.png'
 Time: 00:00.01 (Saving: 00:00.00)

frame: 4
my_float_prop: 20.0
---
Saved: 'C:\tmp\0004.png'
 Time: 00:00.01 (Saving: 00:00.00)

frame: 5
my_float_prop: 20.0
---
Saved: 'C:\tmp\0005.png'
 Time: 00:00.01 (Saving: 00:00.00)

frame: 6
my_float_prop: 20.0
---
Saved: 'C:\tmp\0006.png'
 Time: 00:00.00 (Saving: 00:00.00)

frame: 7
my_float_prop: 20.0
---
Saved: 'C:\tmp\0007.png'
 Time: 00:00.00 (Saving: 00:00.00)

frame: 8
my_float_prop: 20.0
---
Saved: 'C:\tmp\0008.png'
 Time: 00:00.00 (Saving: 00:00.00)

frame: 9
my_float_prop: 20.0
---
Saved: 'C:\tmp\0009.png'
 Time: 00:00.01 (Saving: 00:00.00)

frame: 10
my_float_prop: 20.0
---
Saved: 'C:\tmp\0010.png'
 Time: 00:00.00 (Saving: 00:00.00)

frame: 10
my_float_prop: 20.0
---

So, in a frame_change_post handler, the custom property is animated correctly, but during final render animation it is not updated.

Any update about this issue fix ?