Apply base results in oversized mesh using Catmull-Clark. #75463

New Issue

Frozen_Death_Knight · 2020-04-07T02:03:00+02:00

2020-04-07 02:03:00 +02:00

System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 980/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 442.50

Blender Version
Broken: version: 2.83 (sub 13), branch: master, commit date: 2020-04-12 13:44, hash: 5b79e0b80e
Worked: Never

Short description of error

Exact steps for others to reproduce the error
#75463.blend

Open file
Examine how subdivided object original looks like
Change number of subdivisions in Preview to 0
Click on Apply Base

Compare to form of subdivided mesh

Modified base mesh is slightly oversized.

**System Information** Operating system: Windows-10-10.0.18362-SP0 64 Bits Graphics card: GeForce GTX 980/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 442.50 **Blender Version** Broken: version: 2.83 (sub 13), branch: master, commit date: 2020-04-12 13:44, hash: `5b79e0b80e` Worked: Never **Short description of error** ![untitled.png](https://archive.blender.org/developer/F8467772/untitled.png) **Exact steps for others to reproduce the error** [#75463.blend](https://archive.blender.org/developer/F8467762/T75463.blend) - Open file - Examine how subdivided object `original` looks like - Change number of subdivisions in Preview to 0 - Click on Apply Base # Compare to form of subdivided mesh Modified base mesh is slightly oversized.

Frozen_Death_Knight commented

2020-04-07 02:03:00 +02:00

Added subscriber: @Frozen_Death_Knight

blender-admin commented

2020-04-07 02:03:00 +02:00

#76299 was marked as duplicate of this issue

Frozen_Death_Knight changed title from ~~Catmull-Clark doesn't reflect the edges of the base mesh when using Apply Base on low poly objects (usually the base mesh is too large)~~ to Catmull-Clark doesn't reflect the edges and vertices of the base mesh when using Apply Base on low poly objects (usually the base mesh is too large)

2020-04-07 16:03:24 +02:00

Germano Cavalcante commented

2020-04-08 19:46:53 +02:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2020-04-08 19:46:53 +02:00

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

Germano Cavalcante closed this issue

2020-04-08 19:46:53 +02:00

Germano Cavalcante self-assigned this 2020-04-08 19:46:53 +02:00

Germano Cavalcante commented

2020-04-08 19:46:53 +02:00

This report missed the steps to reproduce the bug.
Videos and/or links to external sites etc. are not acceptable as bug report (they can be provided as additional information).
Sometimes we accept reports when the video is clear about the bug and lasts less than 1 minute.

Please submit a new report and carefully follow the instructions.

A guideline for making a good bug report can be found at https://wiki.blender.org/wiki/Process/Bug_Reports

This report missed the steps to reproduce the bug. Videos and/or links to external sites etc. are not acceptable as bug report (they can be provided as additional information). Sometimes we accept reports when the video is clear about the bug and lasts less than 1 minute. Please submit a new report and carefully follow the instructions. A guideline for making a good bug report can be found at https://wiki.blender.org/wiki/Process/Bug_Reports

Frozen_Death_Knight commented

2020-04-08 20:41:34 +02:00

In #75463#906328, @mano-wii wrote:
This report missed the steps to reproduce the bug.
Videos and/or links to external sites etc. are not acceptable as bug report (they can be provided as additional information).
Sometimes we accept reports when the video is clear about the bug and lasts less than 1 minute.

Please submit a new report and carefully follow the instructions.

A guideline for making a good bug report can be found at https://wiki.blender.org/wiki/Process/Bug_Reports

How exactly is it invalid when I provided the file showing the actual problem and described why the results of Apply Base are wrong? All you need to do is open it, compare the base model with the two models right next to it, and then use Apply Base with Catmull-Clark on the original model to check the results if you want to try it yourself. I even labelled all the models, one of them being what Apply Base should look like after applying it, and the actual result. All of this are already written down in the report.

> In #75463#906328, @mano-wii wrote: > This report missed the steps to reproduce the bug. > Videos and/or links to external sites etc. are not acceptable as bug report (they can be provided as additional information). > Sometimes we accept reports when the video is clear about the bug and lasts less than 1 minute. > > Please submit a new report and carefully follow the instructions. > > A guideline for making a good bug report can be found at https://wiki.blender.org/wiki/Process/Bug_Reports How exactly is it invalid when I provided the file showing the actual problem and described why the results of Apply Base are wrong? All you need to do is open it, compare the base model with the two models right next to it, and then use Apply Base with Catmull-Clark on the original model to check the results if you want to try it yourself. I even labelled all the models, one of them being what Apply Base should look like after applying it, and the actual result. All of this are already written down in the report.

Germano Cavalcante commented

2020-04-08 21:29:15 +02:00

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

Germano Cavalcante reopened this issue

2020-04-08 21:29:15 +02:00

Germano Cavalcante commented

2020-04-08 21:29:16 +02:00

I'll let someone else to triage this one

Germano Cavalcante removed their assignment 2020-04-08 21:29:31 +02:00

Richard Antalik changed title from ~~Catmull-Clark doesn't reflect the edges and vertices of the base mesh when using Apply Base on low poly objects (usually the base mesh is too large)~~ to Apply base results in oversized mesh using Catmull-Clark.

2020-04-12 20:32:08 +02:00

Richard Antalik commented

2020-04-12 20:50:26 +02:00

Added subscribers: @Sergey, @iss

Richard Antalik commented

2020-04-12 20:50:26 +02:00

@Frozen_Death_Knight in your example file object "how apply base looks now" was actually pretty close to subdivided shape, but I could not reproduce such shape. "How it should be" was undersized.

Having said that I don't know if this is bug actually. Will have to ask @Sergey.

@Frozen_Death_Knight in your example file object "how apply base looks now" was actually pretty close to subdivided shape, but I could not reproduce such shape. "How it should be" was undersized. Having said that I don't know if this is bug actually. Will have to ask @Sergey.

Sergey Sharybin commented

2020-04-16 09:15:02 +02:00

"Apple Base" uses a heuristic to reverse the effect of subdivision surface. It is possible to find a better heuristic, but it is quite a large research project which is outside of the scope of the bug tracker.

For now this is considered a known issue.

"Apple Base" uses a heuristic to reverse the effect of subdivision surface. It is possible to find a better heuristic, but it is quite a large research project which is outside of the scope of the bug tracker. For now this is considered a known issue.

Germano Cavalcante commented

2020-04-16 16:23:21 +02:00

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

Vyacheslav Kobozev commented

2020-05-02 13:47:27 +02:00

Added subscriber: @Vyach

Vyacheslav Kobozev commented

2020-05-02 13:47:27 +02:00

It looks, like heuristic assumes, that first subdivide was catmull-clark and it shrinks volume a lot.
And subdivision propogates only between 1—max levels. Otherwise, I can`t understand how simple subdivisions can give same result
Example.

2020-05-02_14-44-24.mp4

Do heuristic takes in account what exact methods of subdivision was done at each level?

It looks, like heuristic assumes, that first subdivide was catmull-clark and it shrinks volume a lot. And subdivision propogates only between 1—max levels. Otherwise, I can`t understand how simple subdivisions can give same result Example. [2020-05-02_14-44-24.mp4](https://archive.blender.org/developer/F8507419/2020-05-02_14-44-24.mp4) Do heuristic takes in account what exact methods of subdivision was done at each level?

Philipp Oeser removed the

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Apply base results in oversized mesh using Catmull-Clark. #75463

Compare to form of subdivided mesh