Designer and Animator Chris Schofield shares a quick tip for making an ordinary IK chain for a character limb in Cinema 4D into a bendy IK limb. If you want to get a more softer, cartoonish arc to how a character’s limb will bend, Chris has come up with a fairly simple solution.
create a more cartoonish based limb rig, whilst still using IK
The basic concept is to have two joint chains, one with a regular bend, and the other that will be spline-based, giving you that bendy IK chain look. You can then use the standard IK chain to drive the bendy IK chain.
A more complex setup, would be to have a rig that could change from a regular sharp-angled IK system to the bendy IK system by switching between the two. This would give the animator the flexibility to move back and forth as the animation would require.
Chris Schofield provides a link to download the example Cinema 4D file that you can play around with or dissect to find out its inner workings.