Regression: Performance with the new Smooth by Angle is significantly slower then auto smooth in 4.0 #117438

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opened 2024-01-23 10:02:15 +01:00 by Daniel Gryningstjerna · 4 comments

Daniel Gryningstjerna commented

2024-01-23 10:02:15 +01:00

Blender Version
Broken: version: 4.1.0 Alpha, branch: main, commit date: 2024-01-23 00:20, hash: b5a9c98e04fa
Worked: 4.0

Short description of error
Auto smooth is way faster in 4.0 comped to 4.1 on the same mesh and same auto smooth angle.

4.0 - 8 fps
4.1 - 15 fps

Exact steps for others to reproduce the error

press G to move around the vertices, notice the performance different between 4.0 and 4.1

**Blender Version** Broken: version: 4.1.0 Alpha, branch: main, commit date: 2024-01-23 00:20, hash: `b5a9c98e04fa` Worked: 4.0 **Short description of error** Auto smooth is way faster in 4.0 comped to 4.1 on the same mesh and same auto smooth angle. 4.0 - 8 fps 4.1 - 15 fps **Exact steps for others to reproduce the error** 1. press G to move around the vertices, notice the performance different between 4.0 and 4.1

Smooth_by_Normal_4.1.blend

25 MiB

Auto_Smooth_4.0.blend

25 MiB

Daniel Gryningstjerna added the

labels 2024-01-23 10:02:15 +01:00

Iliya Katushenock added the

labels 2024-01-23 10:03:53 +01:00

Germano Cavalcante commented

2024-01-23 14:21:33 +01:00

Member

I checked the information provided in #93551 titled "Mesh Normals and Auto Smooth in 4.1".
That document discuss some changes made to the calculation of mesh normals to address performance and usability problems.

However it does not specifically address this issue the performance regression between Smooth by Angle in Blender 4.1 and Auto Smooth in 4.0.

@HooglyBoogly can you provide some insight into this? Is there are any plans to further improve performance in future releases?

Hi @Dangry, I checked the information provided in #93551 titled "Mesh Normals and Auto Smooth in 4.1". That document discuss some changes made to the calculation of mesh normals to address performance and usability problems. However it does not specifically address this issue the performance regression between Smooth by Angle in Blender 4.1 and Auto Smooth in 4.0. @HooglyBoogly can you provide some insight into this? Is there are any plans to further improve performance in future releases?

Germano Cavalcante added

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labels 2024-01-23 14:21:52 +01:00

Hans Goudey commented

2024-01-23 18:57:35 +01:00

Member

Because of the geometry nodes modifier implementation, there will likely be worse performance in edit mode when there are no other modifiers. That's because the modifiers have to convert to Mesh from BMesh. There are a few ways to improve performance in the future:

Make edit mode not require BMesh. That's a large project, but one with many potential benefits.
In geometry nodes, support certain nodes operating directly on BMesh. That would be a limited set of nodes, but if we supported enough to cover this, it might help. Tricky part is that we don't have an original vs. evaluated state of BMesh directly, so that would add complexity.
Don't rely on a modifier in this case, and add some tool setting that updates the flags based on an angle when transforming.

In the meantime, I'd suggest disabling the modifier in edit mode or applying it and using the operator during editing instead.

Because of the geometry nodes modifier implementation, there will likely be worse performance in edit mode when there are no other modifiers. That's because the modifiers have to convert to `Mesh` from `BMesh`. There are a few ways to improve performance in the future: - Make edit mode not require BMesh. That's a large project, but one with many potential benefits. - In geometry nodes, support certain nodes operating directly on `BMesh`. That would be a limited set of nodes, but if we supported enough to cover this, it might help. Tricky part is that we don't have an original vs. evaluated state of BMesh directly, so that would add complexity. - Don't rely on a modifier in this case, and add some tool setting that updates the flags based on an angle when transforming. In the meantime, I'd suggest disabling the modifier in edit mode or applying it and using the operator during editing instead.

Germano Cavalcante commented

2024-01-23 19:55:37 +01:00

Member

Thank you for providing some insight @HooglyBoogly.

So it appears that the conversion from BMesh to Mesh, commonly used in modifiers, can be time-consuming and challenging to handle in this scenario.

The new implementation seems to be a trade-off for a more generic, unified, and improved code, albeit with some performance loss when working in edit mode with a single Auto Smooth node based modifier.

Considering this, it may not be something that can be fixed directly by addressing this specific bug report. Thus, closing for now.
Information explaining this can be added in #93551 or any related documentation.

Looking forward to seeing how this will be improved in the future ;)

@Dangry, thank you for bringing this issue to our attention.

Thank you for providing some insight @HooglyBoogly. So it appears that the conversion from BMesh to Mesh, commonly used in modifiers, can be time-consuming and challenging to handle in this scenario. The new implementation seems to be a trade-off for a more generic, unified, and improved code, albeit with some performance loss when working in edit mode with a single Auto Smooth node based modifier. Considering this, it may not be something that can be fixed directly by addressing this specific bug report. Thus, closing for now. Information explaining this can be added in #93551 or any related documentation. Looking forward to seeing how this will be improved in the future ;) @Dangry, thank you for bringing this issue to our attention.

Germano Cavalcante closed this issue

2024-01-23 19:55:40 +01:00

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labels 2024-01-23 19:55:42 +01:00

Daniel Gryningstjerna commented

2024-01-23 20:37:54 +01:00

Author

@mano-wii @HooglyBoogly
Alright, thanks a lot for the explanation ❤️ I hope we can see an edit mode that can use Mesh in the future. 😄🚀

In the meanwhile, I'll will stick to 4.0 for production work since hiding/applying the smooth by angle modifier is not really an option/solution for me, not considering all the other workflow/performance issues that the new modifier has brought.

While I really like the idea of auto-smooth as a modifier, it has really exposed some real flaws with the current way Blender modifiers work (no support for real instances of a mesh + modifiers) and many other problems that have been brought up all over the community.

I hope all these problems will be solved eventually, especially since Blender is currently built upon a very active hard-surface community.

Unfortunately, many people are going to need to stick to 4.0 for now. But hopefully, someone will make an addon that fixes it, like most problems in Blender. I can't say that I am happy, though, that yet another addon will be needed to fix broken essential core features.😅

@mano-wii @HooglyBoogly Alright, thanks a lot for the explanation ❤️ I hope we can see an edit mode that can use Mesh in the future. 😄🚀 In the meanwhile, I'll will stick to 4.0 for production work since hiding/applying the smooth by angle modifier is not really an option/solution for me, not considering all the other workflow/performance issues that the new modifier has brought. While I really like the idea of auto-smooth as a modifier, it has really exposed some real flaws with the current way Blender modifiers work (no support for real instances of a mesh + modifiers) and many other problems that have been brought up all over the community. I hope all these problems will be solved eventually, especially since Blender is currently built upon a very active hard-surface community. Unfortunately, many people are going to need to stick to 4.0 for now. But hopefully, someone will make an addon that fixes it, like most problems in Blender. I can't say that I am happy, though, that yet another addon will be needed to fix broken essential core features.😅

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