Copy Rotation [world -> world] dosen't work properly with Spline IK chain #85434

New Issue

Kirk Johnson · 2021-02-06T21:03:23+01:00

Kirk Johnson commented

2021-02-06 21:03:23 +01:00

System Information
Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: GeForce GTX 1650/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.79

Blender Version
Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: f6cb5f5449
Worked: version 2.79 and below

Short description of error
The "Copy Rotation" constraint with both 'target' and 'owner' set to 'world', dosen't seems to work as expected, when used on Spline IK chain.
It copies rotation when the target bone is rotating, however it also rotates with the parent bone, even though the Copy Rotation constraint is set to world -> world.
The expected behavior is present in the old versions of blender (2.79 and lower).

Exact steps for others to reproduce the error

Create Spline IK rig with 'root' and 'tip' hook controllers
Set Copy Rotation constraint to bones to copy world rotation of the 'tip' controller

Rotate 'root' controller of the chain and see how bones don't follow rotation of the tip controller

Old version of Blender (2.79)

New version of Blender (2.80)

Video demonstration
bug_demo.mp4

Test rig (saved in 2.79)
spline_ik_twist.blend

**System Information** Operating system: Windows-10-10.0.18362 64 Bits Graphics card: GeForce GTX 1650/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.79 **Blender Version** Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: `f6cb5f5449` Worked: version 2.79 and below **Short description of error** The "Copy Rotation" constraint with both 'target' and 'owner' set to 'world', dosen't seems to work as expected, when used on Spline IK chain. It copies rotation when the target bone is rotating, however it also rotates with the parent bone, even though the Copy Rotation constraint is set to world -> world. ***The expected behavior is present in the old versions of blender (2.79 and lower).*** **Exact steps for others to reproduce the error** - Create Spline IK rig with 'root' and 'tip' hook controllers - Set Copy Rotation constraint to bones to copy world rotation of the 'tip' controller # Rotate 'root' controller of the chain and see how bones don't follow rotation of the tip controller Old version of Blender (2.79) ![spline_ik_twist_old.jpg](https://archive.blender.org/developer/F9676723/spline_ik_twist_old.jpg) New version of Blender (2.80) ![spline_ik_twist_new.jpg](https://archive.blender.org/developer/F9676725/spline_ik_twist_new.jpg) Video demonstration [bug_demo.mp4](https://archive.blender.org/developer/F9676738/bug_demo.mp4) Test rig (saved in 2.79) [spline_ik_twist.blend](https://archive.blender.org/developer/F9676745/spline_ik_twist.blend)

Kirk Johnson commented

2021-02-06 21:03:23 +01:00

Added subscriber: @helloDotJPG

Kirk Johnson commented

2021-02-10 17:52:06 +01:00

Am i the only one who have this issue? This problem literally making some of my old rigs useless.

Kirk Johnson commented

2021-02-17 14:48:33 +01:00

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

Kirk Johnson commented

2021-02-17 14:48:33 +01:00

Hello?

Philipp Oeser commented

2021-02-19 14:09:24 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2021-02-19 14:09:24 +01:00

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

Philipp Oeser commented

2021-02-19 14:09:24 +01:00

Workload in the bugtracker is high atm, so please be a bit more patient, issue will be looked at (but dont change status yourself).

Germano Cavalcante commented

2021-02-20 00:45:27 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2021-02-20 00:45:27 +01:00

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

Germano Cavalcante commented

2021-02-20 00:45:27 +01:00

I simplified the file even more to try to understand what is really different and realized that in blender 2.93 the rotation of the bone parent affects the bone child even if it has a constraint:

As we can see in the GIF, the bone children in 2.79 is not affected by the parent, which seems to be the expected behavior.
Here the simplified file:
parent_affect_child_bug_279.blend

I simplified the file even more to try to understand what is really different and realized that in blender 2.93 the rotation of the bone parent affects the bone child even if it has a constraint: ![GIF.gif](https://archive.blender.org/developer/F9819492/GIF.gif) As we can see in the GIF, the bone children in 2.79 is not affected by the parent, which seems to be the expected behavior. Here the simplified file: [parent_affect_child_bug_279.blend](https://archive.blender.org/developer/F9819499/parent_affect_child_bug_279.blend)

Kirk Johnson commented

2021-02-20 06:25:23 +01:00

In #85434#1115313, @lichtwerk wrote:
Workload in the bugtracker is high atm, so please be a bit more patient, issue will be looked at (but dont change status yourself).

okay, sorry

> In #85434#1115313, @lichtwerk wrote: > Workload in the bugtracker is high atm, so please be a bit more patient, issue will be looked at (but dont change status yourself). okay, sorry

Janusch Patas commented

2021-11-14 18:59:46 +01:00

Added subscriber: @patjan

Kirk Johnson commented

2021-12-03 22:41:28 +01:00

hi guys, is there any update on this issue?

Philipp Oeser removed the

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Copy Rotation [world -> world] dosen't work properly with Spline IK chain #85434

Rotate 'root' controller of the chain and see how bones don't follow rotation of the tip controller