Trouble with Stretch To-constraint


I started to play around with the Stretch To constraint trying to find out different ways I could incorporate it while rigging a character. However, right from the get go I stumbled into this weird problem :

Sometimes when I apply the Stretch To constraint to a certain bone and put some other bone as its target, the whole armature rotates 90 degrees and stays rotated until I remove the constraint. This doesn’t happen always. I’ve managed to do some Stretch To setups just fine.

I haven’t been able to figure out what’s going on. First I thought it had something to do with parenting of the bones (of course it still might) but I’ve tried few different things without results.

Anyone have any experience on this?


I’ve tried different kinds of variations and had no luck. I even made the simplest setup possible (one parent bone, one stretchy bone and one stretch target). It worked fine. Then I made it again and it didn’t work… The whole armature just flips when the stretch to-constraint is added.

I’m using 2.5 A2 by the way so it might be that it is a bug that gets fixed. Just interested to hear if anyone has any experience on the matter and if there is a possible solution.

Try visiting and pull down the latest build. I think the official A2 has had a lot of bug fixes recently.

Stretch To is a tricky one, it can lead to some crazy behavior. Poke around here for a mancandy rig, see his tongue, or pantin, see his head, for workable setups.

edit: there will be hidden bones in various layers involved most likely!

I’ve used stretch to a lot in the Nia rig, on 2.49, and it seems fine. Make sure that in the ‘rest’ position, the root of the target bone and the head of the stretch to bone are at the same location.

Check the console on any versions where you have a problem. If you have a cyclic dependency, the rig tends to twist and/or fall apart.


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This may seem like a silly question, but are you sure you are applying the constraint onto the bone in the bone constraints panel, and not onto the armature object itself in the object constraints panel?

Just for some closure : the problem is gone with the release of 2.53 Beta.

Thanks anyway for the input guys!