Bug 2212099 - Blender subdivision is unusable
Summary: Blender subdivision is unusable
Keywords:
Status: CLOSED WORKSFORME
Alias: None
Product: Fedora
Classification: Fedora
Component: blender
Version: 38
Hardware: x86_64
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Luya Tshimbalanga
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2023-06-03 21:02 UTC by Matthew Woehlke
Modified: 2023-06-05 04:36 UTC (History)
6 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2023-06-05 04:36:15 UTC
Type: Bug
Embargoed:


Attachments (Terms of Use)
Screenshot show how subvidision works (1011.56 KB, image/png)
2023-06-04 17:15 UTC, Luya Tshimbalanga
no flags Details

Description Matthew Woehlke 2023-06-03 21:02:57 UTC
Description of problem:
The subdivision modifier creates extremely broken meshes. Vertices appear to be placed randomly and probably some at infinity.

Version-Release number of selected component (if applicable):
blender-3.5.1-3.fc38.x86_64

How reproducible:
Always?

Steps to Reproduce:
1. Create a new, default document (or create any mesh).
2. Apply subdivision modifier.

Actual results:
The mesh either disappears or produces something that is clearly utter garbage. (If faces are visible at all, they look like noise and are completely black.)

Expected results:
Subdivision works as in 3.3 and 3.4.

Additional info:
blender-1:3.4.1-16.fc38.x86_64 does not seem to be affected.

Comment 1 Luya Tshimbalanga 2023-06-04 17:14:39 UTC
Would you provide a screenshot to see the issue? I failed to reproduce the problem witht eh current version of Blender on AMD Ryzen 7 5825U.

Comment 2 Luya Tshimbalanga 2023-06-04 17:15:55 UTC
Created attachment 1968849 [details]
Screenshot show how subvidision works

Comment 3 Matthew Woehlke 2023-06-05 04:36:15 UTC
That's... interesting. It seems to be behaving itself now.

I've rebooted, but it was doing it from a relatively fresh boot previously.

I'm going to chalk it up to either:
- A *VERY* strange fluke.
- The previous installation was corrupt, somehow.
- Somehow caused by having run 3.3.fc36 previously followed by 3.5.fc38, and somehow fixed after running 3.4.fc38?

I'd been using a somewhat-old version of the fc36 package for some time (circa August 2022 at a guess). A few days ago, Blender wedged my machine (thank you Intel GPU drivers), which I used as an excuse to upgrade to fc38. I installed the latest fc36 version (while the older version was running, I think). I don't recall if I launched the latest fc36 version. I then did a distro-upgrade. After my first boot into fc38, it was broken. I subsequently downgraded to 3.4.fc38, which worked. After upgrading back to 3.5.1-3.fc38, it seems okay. I have no clue if something peculiar to that chain of actions caused it, or what.

As a professional software developer that's sometimes worked with 3D code, I'm confident what I saw was completely bogus and often non-finite vertex positions being generated, probably with invalid normals (i.e. values not in [-1, +1]) as well (explaining why, when I could see *anything*, it was solid black). What would cause *that specifically* (i.e. subdivision) to go haywire without Blender just plain crashing, I have not a clue. Very, very strange.

I guess I'll close this; if it happens again, I'll re-open with a screen shot. Meanwhile, this will be 'on file' in case anyone else runs into the same issue.


Note You need to log in before you can comment on or make changes to this bug.