frame change handlers stop getting triggered after rendering more than 3 to 5 times. #90032

New Issue

michael campbell · 2021-07-22T00:58:48+02:00

michael campbell commented

2021-07-22 00:58:48 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 461.92

Blender Version
Broken: version: 2.93.2 Release Candidate, branch: master, commit date: 2021-07-07 05:52, hash: 9e64fd461a
Worked: (newest version of Blender that worked as expected)

Exact steps for others to reproduce the error
open file and follow instructions in the script editor:

frame change handler only works intermittently when called from code.blend

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 461.92 **Blender Version** Broken: version: 2.93.2 Release Candidate, branch: master, commit date: 2021-07-07 05:52, hash: `9e64fd461a` Worked: (newest version of Blender that worked as expected) **Exact steps for others to reproduce the error** open file and follow instructions in the script editor: [frame change handler only works intermittently when called from code.blend](https://archive.blender.org/developer/F10232664/frame_change_handler_only_works_intermittently_when_called_from_code.blend) ![image.png](https://archive.blender.org/developer/F10232661/image.png)

michael campbell commented

2021-07-22 00:58:48 +02:00

Added subscriber: @3di

Pratik Borhade commented

2021-07-22 04:01:13 +02:00

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

Pratik Borhade commented

2021-07-22 04:01:16 +02:00

Added subscriber: @PratikPB2123

michael campbell commented

2021-07-22 17:58:08 +02:00

This comment was removed by @3di

*This comment was removed by @3di*

Campbell Barton commented

2021-08-10 09:06:23 +02:00

Added subscriber: @ideasman42

Campbell Barton commented

2021-08-10 09:06:23 +02:00

Testing in 2.93 release & master, the second render is always raising an exception:

KeyError: 'bpy_struct[key]: key "file_out_keep" not found'

The second execution sets the the frame, this runs the frame-change handler twice, the second time it runs it can't access the key.

@3di can you confirm if this is the behavior you see too?

Testing in 2.93 release & master, the second render is always raising an exception: `KeyError: 'bpy_struct[key]: key "file_out_keep" not found'` The second execution sets the the frame, this runs the frame-change handler twice, the second time it runs it can't access the key. ---- @3di can you confirm if this is the behavior you see too?

Campbell Barton commented

2021-08-10 09:07:18 +02:00

Changed status from 'Confirmed' to: 'Needs User Info'

michael campbell commented

2021-08-10 10:02:53 +02:00

you shouldn't be getting that, that's a remnant of an old addon. Delete the 'file_out_keep' scene property to resolve that.

Campbell Barton commented

2021-08-10 10:47:12 +02:00

Changed status from 'Needs User Info' to: 'Needs Developer To Reproduce'

Campbell Barton commented

2021-08-10 10:47:12 +02:00

Tested again with 2.93 release and I'm not getting this anymore.

Sergey Sharybin commented

2023-02-15 11:15:27 +01:00

I've looked into the Python code and to me it seems it relies on a specific order and way which and in which order the handlers are run.

The frame-change handler might run prior to render, and it might not be run after the render. This makes the state machine of using finished rendering very fragile.

What happens now is that at the end of the first render finished rendering is created and then the update_on_frame_change is called. Next time you render, the render pipeline calls the frame change handler, which "sees" that the finished rendering property exists and will do things which I believe intention is to only do at the end of the render. Note that the update_on_frame_change is also called after pre_render_job during the first render, so there is no descrepency in the which handlers are called.

I've tried ti simplify the code to make it more visible, hopefully without affecting the overall state machine.

I believe there are more straightforward and robust ways of achieving your goals, but looking into those is outside of a bug fixing process. You are welcome to join and ask for advices in the #python room on the blender.chat.

I've looked into the Python code and to me it seems it relies on a specific order and way which and in which order the handlers are run. The frame-change handler might run prior to render, and it might not be run after the render. This makes the state machine of using `finished rendering` very fragile. What happens now is that at the end of the first render `finished rendering` is created and then the `update_on_frame_change` is called. Next time you render, the render pipeline calls the frame change handler, which "sees" that the `finished rendering` property exists and will do things which I believe intention is to only do at the end of the render. Note that the `update_on_frame_change` is also called after `pre_render_job` during the first render, so there is no descrepency in the which handlers are called. I've tried ti simplify the code to make it more visible, hopefully without affecting the overall state machine. I believe there are more straightforward and robust ways of achieving your goals, but looking into those is outside of a bug fixing process. You are welcome to join and ask for advices in the `#python` room on the blender.chat.

frame_change_simple.blend

25 MiB

Sergey Sharybin closed this issue

2023-02-15 11:15:29 +01:00

Blender Bot added

Status

Archived

and removed

Status

Needs Info from Developers

labels 2023-02-15 11:15:30 +01:00

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