Dan Ebbert’s IK expression, leveling the extremities

[Dan Ebberts]

I’d like to help, but I don’t know what you mean by “leveling the extremities”. Maybe you could clarify.

[Theodore Vojik]

Hey, thanks for your reply 🙂
What I meant was that because the foot (the extremity) is parented to the lower leg, it is rotating with the lower leg – there need to be a counter-rotation of the foot to compensate it.

Your solution in the article was to apply a transform effect, put the “anchorPoint” expression to both anchor and position properties of the effect, and another 2 lines expression to the rotation properties of the transform effect.

Now the problem is that when I apply the “anchorPoint” expression to the anchor/position of the transform effect, the rotation axis is in a weird place and the foot is separated from the lower leg. The counter-rotation expression works well, but the counter-rotation axis is in a wrong place.
I can attach a After effects file if that would be easier,
Thanks a lot Dan

[Dan Ebberts]

Yes, please attach the file.

[Theodore Vojik]

attaching file, the problematic layer is “shoes R” (I marked it in Fuchsia)

Dan-Ebbert-IK.aep 2 MB After Effects Project Files - Click to view

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[Dan Ebberts]

That’s strange. I’m not quite sure what’s going on, but if you turn off the 3 expressions on the Transform effect and use the Transform effect’s crosshairs to position its Anchor Point and Position directly on the layer’s anchor point, and then turn the Rotation Expression back on, you’ll get the leveling.

Or, if you change the Transform effect’s Anchor Point and Position expressions to:

toComp(anchorPoint)

it works. I have no explanation at this point, but it will haunt me.

[Theodore Vojik]

It works! Thank you very much, you’re a genius 🙂

[Brie Clayton]

Thank you, Dan, for this solve!