Rigify: Set the IK Target via Python?

Question

I have a character animation using a rigify human rig. I blocked the animations using different IK Parents for the hand controllers. Before I start splining I want to unify the IK Parent for all my keyframes (above 200 breakdown keys). So I thought using a script to simply loop over all keyframes and set the correct IK parent would be nice. But I don’t know how to execute functions from the rig ui via python

Answer 1

You need to access the pose bones, find the bone that has the IK bone constraint, and modify the subfield target of that constraint.

Here's a small script that prints all of the bones that have IK constraints in a standard rigify generated human rig, and all of their existing targets. Hopefully it will help you figure out the code you need:

import bpy

rig = bpy.context.scene.objects['rig']
            
for bone in rig.pose.bones:
    for constraint in bone.constraints:
        if constraint.type =='IK':
            print(f"{bone.name}: {constraint.subtarget}")

This assumes that you have a generated rig with the default name of rig. Change the name in single quotes in the rig = statement. constraint.subtarget is the value you want to set.

See Kinematic Constraint in the manual for details on the constraint structure.