Why is my IK leg doing this? (Help desperately needed)

Support Animation and Rigging
1

I have no Idea what’s happening here:

Screen Shot 2025-07-30 at 14.35.11 PM
Screen Shot 2025-07-30 at 14.35.11 PM884×1244 210 KB

I tried a IK/FK switch but when I went and did it the IK constraints in keeps doing this after adding the pole. It’s very confusing heres the file for the project (By the way it works fine without the pole):

2

In that file the armature has no IK constraints at the legs.
I’ve added a simple IK to the leg, works.
https://filebin.net/1fqa61p7jahruqc0

Keep in mind that the IK control bone can’t be parented to a bone of the IK chain (cyclic dependencies).

3

Oh shoot I kinda forgot that I deleted them after the photo thanks

4

Also its good but my problem is that after I add the pole it bends weird like in the picture its normal if I don’t add a pole to it but when I do that happens. I tried the same thing on your way to same thing

5

So move the pole

6

Its not like that I tried same thing weird deform happened

7

So you’ve not posted up the correct example file for people to look at…

Looking at your screenshot, I can see the IK leg bones are not pointing at the pole target. There is a setting in the IK constraint called Pole Angle for adjusting that.

Also note that the leg mesh isn’t following the bones. Don’t know if that’s a problem for you and your set up. Normally the mesh should follow the bones 100% unless you have other things influencing the mesh…

Randy

8

I’ll try that and also I made a IK/FK switch that’s why

9

It doesn’t work

10

A couple things:

You have vertex groups doubled up, resulting in some of the strange deformations. Removing Thigh1, Thigh2, and the same for Shin, foot, and toe fixed it for me. Your IK bones should be set to non deform as well, since it looks like you’ve got them set up as control bones, rather than deformers.

Your legs have a bend to them when viewed in front view. I scaled them straight on the X axis, then rotated the whole leg from the ankle, and it seems to be working.

I also recalcalculated the bone rolls. Whatever you due to the IK controls, make sure to also do to the Deform bones as well.

Here’s the file if you want to check it out. I didn’t touch the right leg.

11

Thank you but I tried your model and now when switched to FK the legs bend side ways in the knee area. Also, could you elaborate on what you said please?

12

Also which thigh 1 and thigh 2 etc do you mean like both .L and .R

13

No, i mean there are extra vertex groups on your mesh that are causing issues. I removed them in the file i linked. If you go in a different version there will probably still be vertex groups with names like thigh1.L or similar that youll most likely want to remove.

I didnt have the knee bending problem in the file when i was working on it, and i dont have acces to it right now. When I get a chance I’ll look over it again though.

14

Does this one work any better?https://drive.google.com/file/d/1cDrCHFwVDl0vxxwS3CKxa_6NkoUk7inq/view?usp=sharing

I can try to elaborate on what I did.

  1. I unhid the FK bones
  2. I renamed the FK and IK bones accordingly. It’s not necessary, but it made it easier to tell them apart than thigh1, thigh2, ect… You can leave the names as they were without problem.
  3. I set the FK and IK bones to Non Deform
  4. Unparented the IK foot from the IK shin
  5. Apply the IK constraints with a chain length of 2
  6. I set the pole target to the knee control and adjusted the pole angle.
  7. I parented the knee control to the IK foot (also not necessary, it’s personal preference)
  8. In edit mode I selected the Thigh and Shin of the Normal Legs, the IK Legs, and the FK legs at the same time and recalculated the bone roll on the Y axis.
  9. In edit mode set the pivot point to active element, selected all three of the shins and thighs, then selected the IK Leg.L bone and scaled to zero on the X axis. After that, I rotated the leg back into position, setting the pivot point at the ankle.