Foot rig with 'auto tippy-toe'?

Starting to animate again lately, and yesterday I came across a problem I’d run into before.

As elegant as the automatic ‘heel roll’ type of foot rig (like in Cessen’s Simple Biped, BBB, etc.) is, I always have trouble trying to animate a character going onto tiptoe or jumping. This is because when the trunk ‘root’ (‘pelvis’ in the Simple Biped rig) is translated upward, the entire foot raises up without any of the joints moving. This causes the knees to stay bent unrealistically during rising, or ‘pop’ when I try to counteract it.

Something I think would solve this, and would make animating the legs easier in general, would be for the feet to first go onto tiptoe when the legs are extended (knees locked) by the root bone being translated upward, when the legs are set to IK mode.

Has anyone tried anything like this? Is there a better solution? Any help’s much appreciated!


biped_tiptoe_problem.blend (605 KB)