2 Bugs Reproduced Using Mirror Modifier (UV Bug/Subdivision Subsurface Bug) #90224

New Issue

Shreyansh Sahu · 2021-07-27T08:54:38+02:00

Shreyansh Sahu commented

2021-07-27 08:54:38 +02:00

System Information
Operating system: Windows-10-10.0.22000-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1650/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 471.41

Blender Version
Broken: version: 2.93.1, branch: master, commit date: 2021-06-22 05:57, hash: 1b8d33b18c
Worked: (newest version of Blender that worked as expected)

Short description of error
So There Are 2 Bugs, so i was making blender guru chair tutorial, and he made some Rungs, using MIRROR MODIFIER. So, i was also making, but the first issue is, if i use mirror modifier the subsurf modifier doesnt average nicely, and there is a SHARP EDGE where mirror is happening. 2nd bug while uv unwrapping, it CUTS THAT EDGE OF MIRROR MODIFIER, even tho i applied it, and it is not a seam. I TRIED DOING EVERYTHING WHITHOUT MIRROR MODIFIER AND IT WORKED. SO THE WHOLE PROBLEM IS USING MIRROR MODIFIER

Exact steps for others to reproduce the error
As I said, just add the mirror modifier, it ruins everything.
[Based on the default startup or an attached .blend file (as simple as possible)]Chair With Mirror (BUGGED).blend

Chair Without Mirror (NON-BUGGED).blend

**System Information** Operating system: Windows-10-10.0.22000-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1650/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 471.41 **Blender Version** Broken: version: 2.93.1, branch: master, commit date: 2021-06-22 05:57, hash: `1b8d33b18c` Worked: (newest version of Blender that worked as expected) **Short description of error** So There Are 2 Bugs, so i was making blender guru chair tutorial, and he made some Rungs, using MIRROR MODIFIER. So, i was also making, but the first issue is, if i use mirror modifier the subsurf modifier doesnt average nicely, and there is a SHARP EDGE where mirror is happening. 2nd bug while uv unwrapping, it CUTS THAT EDGE OF MIRROR MODIFIER, even tho i applied it, and it is not a seam. I TRIED DOING EVERYTHING WHITHOUT MIRROR MODIFIER AND IT WORKED. SO THE WHOLE PROBLEM IS USING MIRROR MODIFIER **Exact steps for others to reproduce the error** As I said, just add the mirror modifier, it ruins everything. [Based on the default startup or an attached .blend file (as simple as possible)][Chair With Mirror (BUGGED).blend](https://archive.blender.org/developer/F10240011/Chair_With_Mirror__BUGGED_.blend) [Chair Without Mirror (NON-BUGGED).blend](https://archive.blender.org/developer/F10240012/Chair_Without_Mirror__NON-BUGGED_.blend)

Shreyansh Sahu commented

2021-07-27 08:54:38 +02:00

Added subscriber: @SHREYANSH-SAHU

Shreyansh Sahu commented

2021-07-27 09:18:23 +02:00

Changed status from 'Needs Triage' to: 'Needs Developer To Reproduce'

Shreyansh Sahu commented

2021-07-27 09:19:45 +02:00

Changed status from 'Needs Developer To Reproduce' to: 'Needs Triage'

Philipp Oeser commented

2021-07-27 10:07:21 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2021-07-27 10:07:21 +02:00

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

Philipp Oeser commented

2021-07-27 10:07:21 +02:00

Reproduction steps are not clear, please attach a file where the mirror modifier has not yet been applied and give reproduction steps from there (also make sure to provide settings for the mirror modifier -- I believe you are using Mirror U or Mirror V?)

note #81065 (Applying Subdivision/Multires Modifier De-merges UV's) might be related, but without having a clear repro case, thatis hard to tell.

Reproduction steps are not clear, please attach a file where the mirror modifier has not yet been applied and give reproduction steps from there (also make sure to provide settings for the mirror modifier -- I believe you are using `Mirror U` or `Mirror V`?) note #81065 (Applying Subdivision/Multires Modifier De-merges UV's) might be related, but without having a clear repro case, thatis hard to tell.

Shreyansh Sahu commented

2021-07-27 12:19:28 +02:00

what is mirror u & mirror v? i am new to blender. and i meant it happens when i try to make an object using mirror modifier, if i uv unwrap THE PART WHERE THE OBJECT WAS GETTING MIRRORED "CUTS" THE UV. i also attached same file which i made without mirror modifier and it works fine

Philipp Oeser commented

2021-07-27 12:31:22 +02:00

what is mirror u & mirror v?

i meant it happens when i try to make an object using mirror modifier, if i uv unwrap THE PART WHERE THE OBJECT WAS GETTING MIRRORED "CUTS" THE UV. i also attached same file which i made without mirror modifier and it works fine

so we have a file that already has unexpected results and a file that has expected results, but no way to reproduce the way to get to the unexpected results (because we dont have the file where the mirror modifier has not been applied yet).
It is also not clear what steps have been taken (what exactly does "THE PART WHERE THE OBJECT WAS GETTING MIRRORED "CUTS" THE UV" or "it CUTS THAT EDGE OF MIRROR MODIFIER, even tho i applied it, and it is not a seam" mean?)
Maybe a screencast of what you are doing would help here.

> what is mirror u & mirror v? ![image.png](https://archive.blender.org/developer/F10240484/image.png) > i meant it happens when i try to make an object using mirror modifier, if i uv unwrap THE PART WHERE THE OBJECT WAS GETTING MIRRORED "CUTS" THE UV. i also attached same file which i made without mirror modifier and it works fine so we have a file that already has unexpected results and a file that has expected results, but no way to reproduce the way to get to the unexpected results (because we dont have the file where the mirror modifier has not been applied yet). It is also not clear what steps have been taken (what exactly does "THE PART WHERE THE OBJECT WAS GETTING MIRRORED "CUTS" THE UV" or "it CUTS THAT EDGE OF MIRROR MODIFIER, even tho i applied it, and it is not a seam" mean?) Maybe a screencast of what you are doing would help here.

Shreyansh Sahu commented

2021-07-27 13:44:06 +02:00

How can I screencast to you? should i screen record my video and send or what?

Shreyansh Sahu commented

2021-07-27 13:46:56 +02:00

also i am making one file without applying mirro

Shreyansh Sahu commented

2021-07-27 13:48:35 +02:00

here you go Chair With Mirror Not Applied (BUGGED).blend

here you go [Chair With Mirror Not Applied (BUGGED).blend](https://archive.blender.org/developer/F10240588/Chair_With_Mirror_Not_Applied__BUGGED_.blend)

Shreyansh Sahu commented

2021-07-28 05:36:17 +02:00

Tutorial i was following-
Using mirror- https://www.youtube.com/watch?v=KzA5fOIq8Qw&list=PLjEaoINr3zgEL9UjPTLWQhLFAK7wVaRMR&index=6
UV Unwrap- https://www.youtube.com/watch?v=XeBUfMKKZDo&list=PLjEaoINr3zgEL9UjPTLWQhLFAK7wVaRMR&index=12

Tutorial i was following- Using mirror- https://www.youtube.com/watch?v=KzA5fOIq8Qw&list=PLjEaoINr3zgEL9UjPTLWQhLFAK7wVaRMR&index=6 UV Unwrap- https://www.youtube.com/watch?v=XeBUfMKKZDo&list=PLjEaoINr3zgEL9UjPTLWQhLFAK7wVaRMR&index=12

Shreyansh Sahu commented

2021-07-28 06:42:20 +02:00

waiting for reply...

Shreyansh Sahu commented

2021-07-29 05:28:59 +02:00

been 2 days no reply

Philipp Oeser commented

2021-07-29 07:30:44 +02:00

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

Shreyansh Sahu commented

2021-08-02 05:24:58 +02:00

lol no response, i have even completed that project, but for your knowledge, i figured out the exact problem, while mirroring it made an extra face at mirror origin.

Philipp Oeser commented

2021-08-02 10:30:01 +02:00

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

Philipp Oeser commented

2021-08-02 10:30:01 +02:00

Afaics, the "interior" faces were already present before the mirror.

These dont get merged away.
Do you get the same problems if the faces are removed prior?
Chair With Mirror Not Applied Interior Faces Removed.blend

Afaics, the "interior" faces were already present before the mirror. ![image.png](https://archive.blender.org/developer/F10259318/image.png) ![image.png](https://archive.blender.org/developer/F10259321/image.png) These dont get merged away. Do you get the same problems if the faces are removed prior? [Chair With Mirror Not Applied Interior Faces Removed.blend](https://archive.blender.org/developer/F10259328/Chair_With_Mirror_Not_Applied_Interior_Faces_Removed.blend)

Shreyansh Sahu commented

2021-08-02 13:29:43 +02:00

no

Philipp Oeser commented

2021-08-02 13:34:27 +02:00

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

Philipp Oeser closed this issue

2021-08-02 13:34:27 +02:00

Philipp Oeser commented

2021-08-02 13:34:27 +02:00

OK, thx getting back.
Think we can close this then, because this is actually expected behavior.
(but of course feel free to comment again if issues persist)

OK, thx getting back. Think we can close this then, because this is actually expected behavior. (but of course feel free to comment again if issues persist)

Sign in to join this conversation.

No Label

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

2 Bugs Reproduced Using Mirror Modifier (UV Bug/Subdivision Subsurface Bug) #90224