New Animation Editor breaks after enabling IK

Whenever editing an R15 rig, enabling the IK constraints on the new animation editor prevents you from selecting any of the limbs. The issue persists even after you disable IK but not on new/different dummies.

This bug happens every time, and my friend @ComplexStud is able to replicate on MacOS as well.
To reproduce: Create a new R15 rig (via Rig Builder), enable IK on the rig, try to select any limb.

After enabling IK, the Animation Editor does not seem to pick up most limbs. I was able to select a couple of limbs (Left leg, left hand) but not anything else. They also did not appear in the add limb menu.

The Animation Editor throws an error after trying to enable IK a second time.
Plugin_AnimationClipEditor.rbxm.AnimationClipEditor.Rodux.NoYield:26: Plugin_AnimationClipEditor.rbxm.AnimationClipEditor.Src.Components.IK.IKController:109: attempt to index nil with 'Part1'
Script 'Plugin_AnimationClipEditor.rbxm.AnimationClipEditor.Rodux.NoYield', Line 13 - function resultHandler
Script 'Plugin_AnimationClipEditor.rbxm.AnimationClipEditor.Rodux.NoYield', Line 26 - function NoYield
Script 'Plugin_AnimationClipEditor.rbxm.AnimationClipEditor.Rodux.Store', Line 124 - function flush
Script 'Plugin_AnimationClipEditor.rbxm.AnimationClipEditor.Rodux.Store', Line 46

I can confirm this is happening, you also can’t X out the IK tab after this.

Are there any error logs in your output windows?

Yes, I’ve updated my post with the error message and stack trace (and when it occurs.)
It only errors after trying to enable IK for a second time.

I notice the model you using in the video has it’s named changed from the default “Dummy”. Are there any other instances added to/things changed about this model?

I am unable to replicate this behavior by creating an R15 from Rig Builder and then immediately opening it in the animation editor and going into IK mode. It appears to work fine. I will investigate the error log you provided to get more answers, thanks!

Hey, I actually also updated the video on my thread with a longer video. This one shows me creating a new rig via Rig Builder (default animation rig builder) and the issue still occured.

However, that other model did not have any differences from the default Rig Builder rigs other than the name being changed.

Thanks for the quick response.

Okay, thanks for updating the video. I have been able to reproduce the issue as well. Will keep you updated on when a fix is coming

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Okay, I have a fix. Should be live in about a week from now. I apologize for the inconvenience


Can confirm that this is still an issue on MacOS. Previous rigs used to work and no longer do. I’ve double checked to make sure that the rig follows in-line with the required parameters, which it does.


  1. Create a new place
  2. Rig Builder → R15 → Block Rig
  3. Deselect the newly instanced rig
  4. Click the animation editor
  5. Click IK → Enable IK
  6. Click a limb (in this particular case, I clicked the right hand)
  7. Move and Rotate Tools, when applied to the limb, immediately deselect

Same as above.

This fix should go live tomorrow!


Update: Fix is now live, please do not hesitate to notify me of any other issues. Thanks


Would like to say that this is not fixed. It keeps happening to me with the exact same error to do with Part0 being nil instead of Part1.

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