Rigging a Reverse Foot (Am I doing it wrong?)

I’ve done “Reverse Foot” controls before based on how I learned to do them in Maya, but I noticed something when posing my latest character. Thus far, this is how I’ve created my IK legs: IK_Thigh > IK_Knee > IK_Ankle > IK_Toe / Then duplicate the ankle and toe and switch direction. I would have a third bone from the heel > reverse_toe > reverse_ankle > ik_target.

(2 chain - IK constraint on IK_Knee, target ik_target) works fine
(1 chain - IK constraint on IK_Ankle, target reverse_ankle)
(1 chain - IK constraint on IK_Toe, target reverse_toe)

The problem I am having is when I swivel the heel, the ankle is rotating on it’s y-axis to try and keep z-axis pointing the same direction resulting in a bent toe.


Any help would be much appreciated.

Ya, would really need to see the file to see what you have going on in there. A side view picture would be helpful, at least. TBH, I wasn’t exactly sure what a reverse foot rig was, so I looked it up. It’s pretty much the same as any decent foot rig in blender.

If you’ve done this before in blender, why aren’t you looking at your other files to see where the difference is? At least that’s where I’d start looking at… You might have missed a setting some place on one of the bones.

I’m not familiar with the maya way of doing this sort of foot. I’ve always done a more blender style foot, with a few more helper bones in there. Then again, I only know blender rigging, so It’s the only way I know…

Sorry I can’t be of more help,
Randy

Thank you for replying. I went back to an old file to see if it was different, which it wasn’t. I suspect the problem may have always been there, but I never rotated the foot in this way, thus it went unnoticed. :frowning:

The Rigging101 Reverse Foot tutorial is basically how I learned to do it in Maya. The main difference between Maya and Blender in this case is “IK Handles” aren’t created, but because Blender’s IK Constraint target’s the head of bones, they’re not needed.
One other thing to note is the thigh bone has a single-chain IK constraint. I saw this in a blog post on Digital Tutors. They used this method instead of the pole field. Here is the blend file for some in-depth analysis. I hope this helps solve the problem.

Attachments

GladiatorForumBlend.zip (252 KB)

Took a look at the file and I can see the problem and indeed it appears to be:

But that’s not actually the problem, to me at least. What I’m seeing is when you rotate IKCtrl_Foot.L around like that is the toes are doing what they should be doing, it’s the ankle bone that’s not moving/rotating as it should. The toe bone is pointing in the same direction as the foot controller is.

When I grab the primary foot controller and it’s pivot point is at the heel, like yours is, I expect to be able to move that controller around and the whole foot follows along. When I grab your foot controller and rotate it around to the side, I see the heel moving to the outside, away from the root of the foot controller bone. The toes are pointing the same direction as the foot controller is.

I went back to an old file to see if it was different, which it wasn’t. I suspect the problem may have always been there, but I never rotated the foot in this way, thus it went unnoticed. :frowning:

Do your other rigs using this design suffer from the same problems?

Additionally, when the foot controller is pulled below it’s rest position, the toes of the mesh bend downwards. This is because of the ways the bones are moving. The ik constraint on the toes are targeting a bone that’s being pulled away from the foot, so it’s still pointing as it should, and bending the toes of the mesh while doing it’s job.

Rather than re-invent the wheel, here’s a good blender foot rigging tutorial:
https://www.youtube.com/watch?v=tApdSx_4b0Q
It’s a bit older and a bit more complex than you’re rig, from what I have seen. (I did have to go hunting for hidden bones that were part of you’re set up, so I don’t know if there were even more hidden bones or not). It’s a good rig, but it does use something called an action constraint. I don’t like the action constraint, so I changed somethings around to get away from that constraint, and it’s my goto foot rig for a normal character.

I’m not on my main pc where that file is, but when I can, I will post what I use.

Randy