Rendering scene from VSE of another scene is way slower than render of the scene #110068

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JigenMal · 2023-07-13T17:53:59+02:00

JigenMal commented

2023-07-13 17:53:59 +02:00

System Information
Operating system: Windows-10-10.0.22621-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 4090/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 536.40

Blender Version
Broken: version: 3.6.0, branch: blender-v3.6-release, commit date: 2023-06-27 08:08, hash: c7fc78b81ecb
Worked: (newest version of Blender that worked as expected)

Short description of error
In a multi-scene file with one VSE Edit scene (the workflow suggested by the instructions of the addon "Storypencil - Storyboard tools"), Eevee rendering from the VSE is a lot slower than rendering the single scene. Looks like it's recalculating geometries on each frame.

Exact steps for others to reproduce the error

Load a heavy geometry background that takes Eevee about 10 seconds to render for the first frame in Eevee (I can't provide my scene because of NDA rules)
Create a short camera moving animation, 100 frames at 25fps
choose FFMpeg and MP4 as output format
select 2 samples for Eevee, to speed up render
render animation and verify that the first frame takes about 10 seconds, but the following are way faster to render
create a new scene as "copy settings"
create a video editing workspace
add the original scene in the sequencer
render animation and verify that now every single frame takes 10 seconds: no difference between the first rendered frame and the following.

**System Information** Operating system: Windows-10-10.0.22621-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 4090/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 536.40 **Blender Version** Broken: version: 3.6.0, branch: blender-v3.6-release, commit date: 2023-06-27 08:08, hash: `c7fc78b81ecb` Worked: (newest version of Blender that worked as expected) **Short description of error** In a multi-scene file with one VSE Edit scene (the workflow suggested by the instructions of the addon "Storypencil - Storyboard tools"), Eevee rendering from the VSE is a lot slower than rendering the single scene. Looks like it's recalculating geometries on each frame. **Exact steps for others to reproduce the error** - Load a heavy geometry background that takes Eevee about 10 seconds to render for the first frame in Eevee (I can't provide my scene because of NDA rules) - Create a short camera moving animation, 100 frames at 25fps - choose FFMpeg and MP4 as output format - select 2 samples for Eevee, to speed up render - render animation and verify that the first frame takes about 10 seconds, but the following are way faster to render - create a new scene as "copy settings" - create a video editing workspace - add the original scene in the sequencer - render animation and verify that now every single frame takes 10 seconds: no difference between the first rendered frame and the following.

JigenMal added the

labels 2023-07-13 17:54:00 +02:00

Pratik Borhade commented

2023-07-14 06:20:56 +02:00

Hi, think this is related to other VSE bugs of scene strip rendering: #101269, #106162
Can you confirm?

Hi, think this is related to other VSE bugs of scene strip rendering: #101269, #106162 Can you confirm?

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Pratik Borhade added

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labels 2023-07-14 06:21:13 +02:00

JigenMal commented

2023-07-14 08:55:08 +02:00

Yes, I can confirm that the issue is the same that in #101269, that I can reproduce.
My scene is worse, because the slow scenario described in #101269 has a 1sec/frame render time on my workstation, while the scene I'm working on has 10-12sec/frame, and that makes unusable the workflow officially suggested by the instructions of the "Storypencil - Storyboard tools" addon bundled in Blender.

Yes, I can confirm that the issue is the same that in #101269, that I can reproduce. My scene is worse, because the slow scenario described in #101269 has a 1sec/frame render time on my workstation, while the scene I'm working on has 10-12sec/frame, and that makes unusable the workflow officially suggested by the instructions of the "Storypencil - Storyboard tools" addon bundled in Blender.

JigenMal commented

2023-07-14 09:01:54 +02:00

At the moment my workaround is to launch a "Sequence Render Animation" that has reasonable speed. The problem is that it works only in "Solid" or "Material Preview" shading, and these display modes don't reproduce Grease Pencil effects (that we use in storyboarding/animatic).
Since "Material Preview" scene strip display option in the viewport doesn't have this issue, I'm wondering why the Rendered has it. Isn't still Eevee in charge of Material Preview render? And the issue seems related to geometry reevaluation, not to render settings.

At the moment my workaround is to launch a "Sequence Render Animation" that has reasonable speed. The problem is that it works only in "Solid" or "Material Preview" shading, and these display modes don't reproduce Grease Pencil effects (that we use in storyboarding/animatic). Since "Material Preview" scene strip display option in the viewport doesn't have this issue, I'm wondering why the Rendered has it. Isn't still Eevee in charge of Material Preview render? And the issue seems related to geometry reevaluation, not to render settings.

Pratik Borhade commented

2023-07-14 09:18:32 +02:00

Thanks.
I guess the decrease in render time is because VSE-render reinitializes context and resources for every frame as said in: #101269 (comment)

regular animation render keeps a lot of contexts alive throughout the render

sequencer creates dependency graph and all the render contexts and GPU resources for every frame it renders from the scene strip, and destroys them when the frame is rendered

Will close this as duplicate if this is same as the other report.

Isn't still Eevee in charge of Material Preview render?

They are same. Only difference is EEVEE uses scene lights and material preview shading uses HDR (but this can be changed anytime from viewport shading popover)

Thanks. I guess the decrease in render time is because VSE-render reinitializes context and resources for every frame as said in: https://projects.blender.org/blender/blender/issues/101269#issuecomment-102845 > - regular animation render keeps a lot of contexts alive throughout the render > - sequencer creates dependency graph and all the render contexts and GPU resources for every frame it renders from the scene strip, and destroys them when the frame is rendered - - - Will close this as duplicate if this is same as the other report. > Isn't still Eevee in charge of Material Preview render? They are same. Only difference is EEVEE uses scene lights and material preview shading uses HDR (but this can be changed anytime from `viewport shading` popover)

Pratik Borhade closed this issue

2023-07-14 09:18:34 +02:00

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labels 2023-07-14 09:18:37 +02:00

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