Rigs - No Going Back?

Has anyone else noticed this?

I built this mechanical rig in Blender 2.65 r54095. I then had reason to open it in r53189 (2.65a release if I’m not mistaken) and found the following had happened:


Just to be clear, the above image shows r53189 on the left which is actually ‘after’ and r54095 on the right which is ‘before.’

Is this a bug or has there been a fundamental change in how mesh objects are parented to bones in recent revisions?

I also tried loading this file into the latest BuildBot version (r54348), saving it back out and opening the resulting file in 2.65a and the same thing happened.

I don’t know for sure if I’ll ever need to go back to an earlier version, but if I do, this will definitely get in the way.

And BTW, saving as a legacy mesh doesn’t help. This seems to have something to do with recent armature changes.

The only entry in the SVN Logs mentioning armatures since the 2.65a release is this:

Bugfix [[#34123](http://projects.blender.org/tracker/index.php?func=detail&aid=34123)] Armature "Switch Direction" doesn't work when selected bone
belongs to more than one chain

For example:
               /----->C
   A-->B-:
               ----->D

If bone B is selected, then it would get operated on twice, creating the
illusion that it had not been operated on. This is because we traverse up the
chains (child to parent) as the EditBone structure only stores parent to
children relationships only. A second invocation of this operator would then
work fine, as all the links to other bones would have been removed, thus
preventing further problems.

Fixed by tagging bones that have been operated on.

As you can see, it does talk about a change in parent/child relationships within a bone chain, but is it possible something got changed that affects mesh/bone parenting as well?

If someone else could try this procedure with their own mechanical rigs, I’d be very grateful for any insights derived therefrom:

  • build a mechanical rig in a recent build (post-2.65a) from BuildBot,
  • load it into 2.65a release (r53189).

See here: http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.66/Usability#Animation_fixes

Specifically, it is the “Relative Parenting” option that Ton added which causes this problem and not the commit mentioned above.

Thanks for pointing that out to me, Aligorith.

Turns out there’s a relatively quick fix for this, anyway. Just un-parent and re-parent each mesh and everything falls back into place.

I don’t understand what Relative Parenting is all about, though. Can you explain it? Ton mentions being able to move the pivot point while in Edit Mode, but that capability was already in there.

He also talks about how child objects can now transform in a similar way to bone deformations, but that’s going right over my head.

Are these changes something an animator will use, or are they just an internal thing that makes coding easier?