Super simple IK setup is broken on Godot 4, help

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:bust_in_silhouette: Asked By Jamsers

CCDIK, FABRIK, and TwoBoneIK all seem to be broken in their own peculiar ways, and I’ve been pulling my hair out trying to get this basic IK setup working.

I’ve got a super simple humanoid rig (I’m talking so simple it doesn’t even have hands or feet) and I want to be able to rotate the body while keeping the legs grounded.

I’ve got it setup properly to the best of my knowledge and the only one that gives barely usable results is CCDIK, and even then, applying joint constraints breaks it!

If anyone has any kind of experience with Godot animation, please take a look at my minimal repro project! Maybe there’s some kind of basic mistake I’m making!

Here’s the minimal repro project with source .blend file for the character:

I tested your scene and can see your problems with every variant. I’m not knowledgeable enough when working with Skeleton3D, so I don’t know if your setup is wrong or the implementation is really messed up in the current Beta.

You can take a look at the issue list of the PR #63588 Modification stack to nodes - maybe your problems are already documented in some of these issues. If not, it might be a good idea to create another issue with your project file (because it seems to be a good minimal reproduction scene), add some videos and link to that PR to make fire aware of it.

rolfpancake | 2022-12-08 07:50

Yeah, I’ve reported the issue on Github, at the very least we can get confirmation if it’s a Godot issue or a setup issue: #69752

Jamsers | 2022-12-08 08:53