Mechanical Robot IK Leg Rig Problem

[Kestutis_Jankunas]

Can someone assist/help me to get this IK leg working, somehow i cant seem to get the foot working with the IK. Bottom hinge (middle red hinge) doesn't seem to be able to align with the leg. Foot controller is suppose to control the rotation of the foot whilst knee locator aligning knee with pole vector.

Tried multiple different setups yet i  always get close but nothing seems to work, it always breaks at one point or another. Every other post seems to suggest that it is not possible which seems bizarre as it feels to simple of a task to be true. Majority of answer are either universal joint or FK solution but I am curious of IK solution also without affecting design/concept of the model.


Also to add, its Rotate Plane Solver IK from hips to ankle and ankle to foot as well as foot to each toe its Single Chain IK, everything has its own group with pivot at the ankle and everything is grouped under name of toe roll group to be able to toe roll the foot controller should controller position of foot also the forward and backward rotation (X Axis) Rotation of foot controllers Y Axis should rotate the foot on its foot cylinder plate, but not affect ankle hinge Y rotation. Also was trying to achieve this by having foot controller always being aligned to foot.


Thanks in advance!

[Kestutis_Jankunas]

Without Single Chain IK's it works fine but it loses toe roll functionality as well as some Inverse Kinematic functions later down the line. Also wanted to add, preferably one foot controller that controls entire leg and foot.

Any solution or idea is welcome!

[Kahylan]

Hi!

Since both your Knee and your Foot are one directional hinge joints, the integrity of your leg model breaks as soon as they misalign. Having both a IK Pole control and a Foot control that allows for multidirectional rotation does not make sence with this model.

I would suggest using the foot control to drive the pole vector/Knee direction, by having the Polevector off to the side with a 90 degree offset in the main Axis and parented under the foot control. Similar to IK noFlip setups used for easy walk and run cycle animation. This allows you to have the foot control as the universal IK Leg control and drive both direction and bend of your leg.

Also, obviously with your model, side to side rotation does not make sence with the joint so it should be locked.

I hope it helps!

[Kestutis_Jankunas]

Thanks for response!

I will get more in depth with your answer when i got time as well as upload scene file when i got time.

I figure that much that if ankle be changed to a ball joint design it would be no hassle with the IK rig, however this changes the design of the character. Still surprised this setup does not work since it does have 2 axis rotation on the ankle (1 axis for one joint and another axis for another joint its two separate meshes) which should be more than enough as the Z (third axis) should always be aligned with knee.

Still curious if this design would be possible, if nothing else changes must be made haha

Attached 2nd photo that shows rotations that are controllable by foot controller.