Sub-surf is very slow on high edge-count vertex poles #59333

New Issue

Aaron Fjerstad · 2018-12-13T21:25:13+01:00

Aaron Fjerstad commented

2018-12-13 21:25:13 +01:00

System Information
Operating system: Windows 10
Graphics card: GeForce GTX 1050 TI

Blender Version
Broken: blender-2.80.0-git.7d4d9e9dbd3-windows64
Worked: blender-2.79b

Short description of error
NOTE: This is similar to bug (#58191), but different, as I'll explain after the steps.

When a single subdivision surface modifier with 1 subdivision is placed on an object with a high edge-count vertex, it all but stops working.

Exact steps for others to reproduce the error

Open default startup and delete everything.
Add a cylinder with 128 vertices and a triangle fan cap (even worse with n-gon).
Add a subdivision surface modifier with 1 subdivision.
Go into edit mode.
Listen to your fan scream.

How it's different from the aforementioned bug:

The face count for this cylinder is only 384, as compared to 500 faces of the monkey mesh, but adding the same simple modifier to the monkey has no issue. The primary difference I can see is that the cylinder has vertices with a high edge count.

If you follow the same steps in Blender 2.79b, the problem does not occur, which leads me to believe there are some wrinkles in the Catmull-Clark implementation for 2.8 that need to be ironed out.

Thank you.

**System Information** Operating system: Windows 10 Graphics card: GeForce GTX 1050 TI **Blender Version** Broken: blender-2.80.0-git.7d4d9e9dbd3-windows64 Worked: blender-2.79b **Short description of error** NOTE: This is similar to bug (#58191), but different, as I'll explain after the steps. When a single subdivision surface modifier with 1 subdivision is placed on an object with a high edge-count vertex, it all but stops working. **Exact steps for others to reproduce the error** 1. Open default startup and delete everything. 2. Add a cylinder with 128 vertices and a triangle fan cap (even worse with n-gon). 3. Add a subdivision surface modifier with 1 subdivision. 4. Go into edit mode. 5. Listen to your fan scream. How it's different from the aforementioned bug: The face count for this cylinder is only 384, as compared to 500 faces of the monkey mesh, but adding the same simple modifier to the monkey has no issue. The primary difference I can see is that the cylinder has vertices with a high edge count. If you follow the same steps in Blender 2.79b, the problem does not occur, which leads me to believe there are some wrinkles in the Catmull-Clark implementation for 2.8 that need to be ironed out. Thank you.

Aaron Fjerstad commented

2018-12-13 21:25:13 +01:00

Added subscriber: @AaronFjerstad

blender-admin commented

2018-12-13 21:25:13 +01:00

#62616 was marked as duplicate of this issue

blender-admin commented

2018-12-13 21:25:13 +01:00

#60529 was marked as duplicate of this issue

blender-admin commented

2018-12-13 21:25:13 +01:00

#58503 was marked as duplicate of this issue

Sebastian Parborg changed title from ~~Simple sub-surf breaks on high edge-count vertex~~ to Sub-surf is very slow on high edge-count vertex poles

2018-12-14 15:33:58 +01:00

Sebastian Parborg commented

2018-12-14 15:37:51 +01:00

Added subscribers: @Sergey, @ZedDB

Sergey Sharybin was assigned by Sebastian Parborg

2018-12-14 15:37:51 +01:00

Sebastian Parborg commented

2018-12-14 15:37:51 +01:00

It seems like opensubdiv is very slow when having meshes with extreme cases of vertex poles.

Don't know if there is much to do about this. What do you think @Sergey ?

It seems like opensubdiv is very slow when having meshes with extreme cases of vertex poles. Don't know if there is much to do about this. What do you think @Sergey ?

Sebastian Parborg commented

2018-12-19 16:32:25 +01:00

Added subscribers: @tobikubi, @lichtwerk, @moisessalvador

Brecht Van Lommel commented

2019-01-15 13:19:17 +01:00

Added subscriber: @gentleclockdivider

Brecht Van Lommel commented

2019-03-15 16:04:16 +01:00

Added subscriber: @JacquesLucke

ward commented

2019-03-15 18:40:50 +01:00

same happens with no ngons
Just insert the subdiv. on this model ( low poly )
this .blend

same happens with no ngons Just insert the subdiv. on this model ( low poly ) [this .blend](https://archive.blender.org/developer/F6830679/this_.blend)

Pablo Couto commented

2019-08-07 16:35:18 +02:00

Added subscriber: @pabcou

Evan Wilson commented

2019-12-20 02:18:42 +01:00

Added subscriber: @EAW

Evan Wilson commented

2019-12-20 02:18:42 +01:00

According to http://graphics.pixar.com/opensubdiv/docs/mod_notes.html

High valence vertices incur fairly large performance hits
Currently, OpenSubdiv has a hard constraint imposed by GPU shaders on the maximum valence of a vertex (~27 on current hardware)

According to http://graphics.pixar.com/opensubdiv/docs/mod_notes.html * High valence vertices incur fairly large performance hits * Currently, OpenSubdiv has a hard constraint imposed by GPU shaders on the maximum valence of a vertex (~27 on current hardware)

Sergey Sharybin was unassigned by Dalai Felinto

2019-12-23 16:35:38 +01:00

Richard Antalik commented

2020-01-23 00:18:18 +01:00

Closed as duplicate of #60733

Richard Antalik closed this issue

2020-01-23 00:18:18 +01:00

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Sub-surf is very slow on high edge-count vertex poles #59333