The new IK solvers don't work as expected with a joint limitation

Help Physics
1

Godot Version

v4.6.beta.mono.arch_linux [63227bbc8]

Question

Hi. The new IK chain solvers, such as FABRIK3D or JacobianIK3D, don’t seem to work as expected when the rotation is limited by a JointLimitationCone3D.

I added a FABRIK3D to my humanoid rig to fix its feet to target 3D nodes which works as intended initially:

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However, when I restrict the rotation radius to prevent the joint from bending in the wrong way, it fails to solve proper positions for the end bones:

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I think I got the joint cone’s orientation right, from the way the legs bend when I adjust its radius.

Could anyone help me with this problem?

Thanks in advance!

2

Adding constraints makes it more difficult to solve, and the solver will give up after it tries max iterations. Try increasing the max iterations? The only other thing I could think is that there is something also constraining the other bone in the chain making the solution impossible.

Edit: It had been a while since I played with IK, and I am reproducing this behavior in my own scene. You are right. The JointLimitationCone3D doesn’t seem to be constraining things in a way one would expect.