Transforms: Relative Mirror with negative rotation can act like a dependency cycle #95396

New Issue

Demeter Dzadik · 2022-02-01T15:20:20+01:00

Demeter Dzadik commented

2022-02-01 15:20:20 +01:00

System Information
Operating system: Linux-5.15.11-76051511-generic-x86_64-with-glibc2.34 64 Bits
Graphics card: NVIDIA GeForce RTX 2080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 470.86

Blender Version
Broken: version: 3.2.0 Alpha, branch: master, commit date: 2022-02-01 13:59, hash: 32b33e91eb
Worked: Unknown, possibly never?

Short description of error
With "X-Axis Mirror" and "Relative Mirror" pose options enabled, when both left and right sides of a bone are selected, they have a negative X rotation, and you try to translate them, they turn into a happy little helicopter and float away:
x_mirror_helicopter-2022-02-01_15.16.21.mp4

Exact steps for others to reproduce the error

File: pose_mirror_madness.blend
Try translating the two selected bones using either G hotkey or the transform gizmo. It should break.
If you only select one bone, it works.
If Relative Mirror is off, it works.
If the X rotation of the bones is not negative, it works.

Very specific bug...! The behaviour reminds me of when there is a dependency cycle in a rig, so I assume when both left and right sides are selected, they are trying to write into each other's transforms at the same time, resulting in madness.

**System Information** Operating system: Linux-5.15.11-76051511-generic-x86_64-with-glibc2.34 64 Bits Graphics card: NVIDIA GeForce RTX 2080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 470.86 **Blender Version** Broken: version: 3.2.0 Alpha, branch: master, commit date: 2022-02-01 13:59, hash: `32b33e91eb` Worked: Unknown, possibly never? **Short description of error** With "X-Axis Mirror" and "Relative Mirror" pose options enabled, when both left and right sides of a bone are selected, they have a negative X rotation, and you try to translate them, they turn into a happy little helicopter and float away: [x_mirror_helicopter-2022-02-01_15.16.21.mp4](https://archive.blender.org/developer/F12839324/x_mirror_helicopter-2022-02-01_15.16.21.mp4) **Exact steps for others to reproduce the error** - File: [pose_mirror_madness.blend](https://archive.blender.org/developer/F12839328/pose_mirror_madness.blend) - Try translating the two selected bones using either G hotkey or the transform gizmo. It should break. - **If you only select one bone**, it works. - If Relative Mirror is off, it works. - If the X rotation of the bones is not negative, it works. Very specific bug...! The behaviour reminds me of when there is a dependency cycle in a rig, so I assume when both left and right sides are selected, they are trying to write into each other's transforms at the same time, resulting in madness.

Demeter Dzadik commented

2022-02-01 15:20:20 +01:00

Added subscriber: @Mets

Germano Cavalcante commented

2022-02-01 21:51:10 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2022-02-01 21:51:10 +01:00

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

Germano Cavalcante commented

2022-02-01 21:51:10 +01:00

I can confirm the problem. It looks like there is a transformation cycle (one transforming mirrored bone has its position overwritten which is used to override the position of the other).

Philipp Oeser removed the

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Transforms: Relative Mirror with negative rotation can act like a dependency cycle #95396