Maniphest T28313

Adding pole target to IK chain makes IK ignore limits set further up the chain
Closed, Archived
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Assigned To
Brecht Van Lommel (brecht)
Authored By
Peter Schulman (astralpancakes)
Aug 21 2011, 1:56 PM
Tags
  • Animation & Rigging
  • BF Blender
Subscribers
Brecht Van Lommel (brecht)
Henning Roos (Hinnyboy)
koil (koilz)
Peter Schulman (astralpancakes)

Description

Scroll timeline in attached .blend file to see what's up.

armatureA and armatureB are otherwise the same, only B has a pole target set for the IK constraint on bone2. Rotation limits set on bone2 are handled correctly on both armatures (neither is ever completely straight, because X rotation is limited), but on armatureB, limits set on bone1 are ignored.

Related Objects

Event Timeline

Peter Schulman (astralpancakes) edited a custom field.Aug 21 2011, 1:56 PM
Peter Schulman (astralpancakes) attached 1 file(s): F14803: poleTarget.blend.
Brecht Van Lommel (brecht) added a comment.Aug 22 2011, 1:57 PM

It's a known limitation of this option, see here:
http://www.blender.org/development/release-logs/blender-246/inverse-kinematics/

Brecht Van Lommel (brecht) changed the task status from Unknown Status to Archived.Aug 22 2011, 1:57 PM
koil (koilz) added a subscriber: koil (koilz).Feb 18 2014, 8:16 PM

I was wondering if this bug could be reopened, or added to the new todo list on the wiki, or a explaination to why it cant be fixed.
I recently found this bug or limitation a problem while rigging.

Some reasons to IK lock the final chain bone:

  • Prevent a finger from spinning on the Y axis.
  • Prevent shoulder joint from spinning on the Y axis.

Old wiki reference seems to be gone: http://wiki.blender.org/index.php/Dev:Ref/Outdated/Release_Notes/2.46
New file with same problem:

ik_pole_lock.blend340 KBDownload
Problem is documented in the Text Editor.

With an IK bone constraint, the last bone in the chain cannot be XYZ locked if using a pole target.

Henning Roos (Hinnyboy) added a subscriber: Henning Roos (Hinnyboy).Oct 23 2017, 8:59 PM
Henning Roos (Hinnyboy) changed the task status from Archived to Unknown Status.Oct 23 2017, 9:10 PM

Why is this issue ignored? Please revisit this issue.

Brecht Van Lommel (brecht) changed the task status from Unknown Status to Archived.EditedOct 23 2017, 9:22 PM
Brecht Van Lommel (brecht) claimed this task.

Please do not reopen old bug reports.

There is no particular reason this feature can't be implemented, it just takes quite a bit of work. For requesting features like this, see here:
https://wiki.blender.org/index.php/Dev:Doc/Contact#Requesting_Features

Brecht Van Lommel (brecht) mentioned this in T96339: IK: Axis locks not respected when using IK Pole.Mar 16 2022, 1:14 PM