Face deformations on belly adjustments (with no belly changes rendered)

[metaleap]

As described previously on Discord:

I have recorded what's happening (pasted below, ~45s long, only starting at 20s in), be sure to watch the mouth/nose/chin/ear areas as I drag the belly sliders, and how nothing about the belly changes while those facial details grow some jaggily-distorted geometry extrusions somehow:

https://github.com/user-attachments/assets/bc1e4915-c59c-49f0-8774-878fa9159884

This applies across all Viewport Shading modes and both renderers.

Launching Blender from terminal, I found these lines at startup:

charmorph addon: Verbose is enabled
charmorph addon: Read in JSON settings from file
WARN (bpy.rna): /usr/src/debug/blender/blender/source/blender/python/intern/bpy_rna.cc:1360 pyrna_enum_to_py: current value '0' matches no enum in 'CharMorphUIProps', '', 'rig'

Then when I click Import Character, another debug print in the terminal:

/home/_/.config/blender/4.2/scripts/addons/CharMorphGit/lib/morphs.py:162: RuntimeWarning: overflow encountered in scalar add
  pos2 = part_pos + i

No other prints evermore after that, as I drag sliders around etc.

System details: up-to-date Garuda Linux (not that distro really matters), kernel 6.11.1-zen1-1-zen, KDE 6 on X11, Nvidia RTX 4090 GPU with proprietary drivers (also up-to-date).

This was encountered both with the proper release download for v0.3.5 and with a recursively-cloned version on commit b54a1f21d91e4b7018dbf2f0363b2fedf9944425, installed only after a clean uninstall of the previously installed version.

blender --version output:

Blender 4.2.1 LTS
        build date: 2024-09-01
        build time: 08:21:56
        build commit date: 2024-08-19
        build commit time: 11:21
        build hash: 396f546c9d82
        build branch: makepkg (modified)
        build platform: Linux
        build type: Release
        build c flags:  -Wall -Werror=implicit-function-declaration -Wstrict-prototypes -Werror=return-type -Werror=vla -Wmissing-prototypes -Wno-char-subscripts -Wno-unknown-pragmas -Wpointer-arith -Wunused-parameter -Wwrite-strings -Wlogical-op -Wundef -Winit-self -Wmissing-include-dirs -Wno-div-by-zero -Wtype-limits -Wformat-signedness -Wrestrict -Wno-stringop-overread -Wno-stringop-overflow -Wnonnull -Wabsolute-value -Wuninitialized -Wredundant-decls -Wshadow -Wimplicit-fallthrough=5 -Wno-error=unused-but-set-variable -march=x86-64 -mtune=generic -O2 -pipe -fno-plt -fexceptions         -Wp,-D_FORTIFY_SOURCE=3 -Wformat -Werror=format-security         -fstack-clash-protection -fcf-protection         -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -g -ffile-prefix-map=/build/blender/src=/usr/src/debug/blender -march=x86-64-v2 -fopenmp -std=gnu11 -pipe -fPIC -funsigned-char -fno-strict-aliasing -ffp-contract=off  
        build c++ flags:  -Wuninitialized -Wredundant-decls -Wall -Wno-invalid-offsetof -Wno-sign-compare -Wlogical-op -Winit-self -Wmissing-include-dirs -Wno-div-by-zero -Wtype-limits -Werror=return-type -Wno-char-subscripts -Wno-unknown-pragmas -Wpointer-arith -Wunused-parameter -Wwrite-strings -Wundef -Wcomma-subscript -Wformat-signedness -Wrestrict -Wno-suggest-override -Wuninitialized -Wno-stringop-overread -Wno-stringop-overflow -Wimplicit-fallthrough=5 -Wundef -Wmissing-declarations -march=x86-64 -mtune=generic -O2 -pipe -fno-plt -fexceptions         -Wp,-D_FORTIFY_SOURCE=3 -Wformat -Werror=format-security         -fstack-clash-protection -fcf-protection         -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer  -g -ffile-prefix-map=/build/blender/src=/usr/src/debug/blender -march=x86-64-v2 -fopenmp -pipe -fPIC -funsigned-char -fno-strict-aliasing -ffp-contract=off  
        build link flags:  -Wl,--version-script='/build/blender/src/blender/source/creator/symbols_unix.map' -latomic
        build system: CMake

Full system details in blender-system-info.txt

I have verified that this also occurs with all other Add-Ons disabled (except the built-in ones), so it's not like any of them interfere or some such =)

It also occurs with "Adult Mode" off and with both Undo Modes (Simple & Advanced).

[metaleap]

Btw it's not due to Nvidia, just tried on another (lower-end) machine with the exact-same setup (distro, kernel, Blender, Python, KDE versions all identical to above) but a different GPU that self-reports as "AMD ATI 05:00.0 Barcelo" (but sticker on machine says AMD Radeon) — exactly the same quirk as in the above vid.

[seenbuklee]

Could you test with a Python 3.11 or an earlier version of Blender. Maybe 4.1?

[metaleap]

@Hopefullyidontgetbanned whoa! Problem does not occur with 4.1.1! Which also embeds and uses Python 3.11.7.

[seenbuklee]

I'm using 4.2.1 with python 3.11.7 embed, so maybe Blender uses the system version if it's newer? Since my system version is 3.11.4

[metaleap]

Probably! I can by now confirm that the bug here is definitely about the Python version: Just fetched 4.2.2 from blender.org which embeds and uses 3.11.7 (I checked) instead of my system-wide Python 3.12.6, and the bug is also gone here in that 4.2.2.

So I'll use the downloaded Blender instead of the Octopi-installed Blender for now, until a future fix lands. =)

[seenbuklee]

well blender chooses Python versions incredibly deliberately for reasons like this. They update their libraries in a more deliberate reason. so i don't know why someone just swapped versions around.