Some Bones get slightly offset from Binding/Edit pose in Pose/Object mode #90125

New Issue

Konstantins Visnevskis · 2021-07-25T16:03:52+02:00

2021-07-25 16:03:52 +02:00

System Information
Operating system: Linux-5.8.0-59-generic-x86_64-with-glibc2.31 64 Bits
Graphics card: GeForce GTX 560/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 390.143

Blender Version
Broken: version: 2.93.1, branch: master, commit date: 2021-06-22 05:57, hash: 1b8d33b18c

Short description of error
As per usual procedure of chasing out rigged character twitches (rest pose differences from edit pose), I've stumbled upon one that seems to have nothing but bone configuration as the source.
Chain of Bones in particular coordinates produces an offset at the last bone tail when switching to/from edit mode (constraints/animation erased).
It was a longer bone chain but those not affecting the result were deleted.
Recreating bones from scratch in identical coordinates/rolls produced the same offset but in another direction.
Calculation precision insufficiency?

Exact steps for others to reproduce the error
stretch1.blend

Open,
Switch to/from Edit/Pose or Edit/Object modes.

**System Information** Operating system: Linux-5.8.0-59-generic-x86_64-with-glibc2.31 64 Bits Graphics card: GeForce GTX 560/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 390.143 **Blender Version** Broken: version: 2.93.1, branch: master, commit date: 2021-06-22 05:57, hash: `1b8d33b18c` **Short description of error** As per usual procedure of chasing out rigged character twitches (rest pose differences from edit pose), I've stumbled upon one that seems to have nothing but bone configuration as the source. Chain of Bones in particular coordinates produces an offset at the last bone tail when switching to/from edit mode (constraints/animation erased). It was a longer bone chain but those not affecting the result were deleted. Recreating bones from scratch in identical coordinates/rolls produced the same offset but in another direction. Calculation precision insufficiency? **Exact steps for others to reproduce the error** [stretch1.blend](https://archive.blender.org/developer/F10236921/stretch1.blend) - Open, - Switch to/from Edit/Pose or Edit/Object modes.

Konstantins Visnevskis commented

2021-07-25 16:03:52 +02:00

Added subscriber: @KonstantinsVisnevskis

Konstantins Visnevskis changed title from ~~Bone precision?~~ to Bones get slightly offset from Binding/Edit pose in Pose/Object mode

2021-07-25 16:05:31 +02:00

Konstantins Visnevskis changed title from ~~Bones get slightly offset from Binding/Edit pose in Pose/Object mode~~ to Some Bones get slightly offset from Binding/Edit pose in Pose/Object mode

2021-07-25 16:07:01 +02:00

Philipp Oeser commented

2021-09-27 14:28:57 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2021-09-27 14:28:57 +02:00

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

Philipp Oeser commented

2021-09-27 14:28:57 +02:00

Can confirm this one.
This goes away when Inherit Rotation is unchecked on that specific bone (that is probably clear - just pointing out since clearing rotation on all bones makes no difference)

Can confirm this one. This goes away when `Inherit Rotation` is unchecked on that specific bone (that is probably clear - just pointing out since clearing rotation on all bones makes no difference)

Konstantins Visnevskis commented

2021-12-03 12:10:33 +01:00

Found one more. The offset is larger, and is magnified even more (possibly happening more times in a row) on the complete rig, resulting in about 2-3mm foot offset on a cat, which is a visible transformation.
The offset seems to decrease when bone spine_fk.001 is not as close to horizontal (in Edit Mode) and disappears when it gets completely horizontal, suggesting possible calculation precission insufficiency.
bones.blend

Found one more. The offset is larger, and is magnified even more (possibly happening more times in a row) on the complete rig, resulting in about 2-3mm foot offset on a cat, which is a visible transformation. The offset seems to decrease when bone spine_fk.001 is not as close to horizontal (in Edit Mode) and disappears when it gets completely horizontal, suggesting possible calculation precission insufficiency. [bones.blend](https://archive.blender.org/developer/F12685796/bones.blend)

Philipp Oeser removed the

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Some Bones get slightly offset from Binding/Edit pose in Pose/Object mode #90125