Currently I am trying the Annimation Rigging package on a mechanical walker with 3 boned legs.
However I can not seem to figure out how to correctly handle 3 bones.
The image attached shows me the setup of a leg.
The green one is the sholder so to say, while can rotate freely, the purple is the end point.
Then the red ones are used to fold and extend the leg, and this is the part I am unable to figure out. The red ones can only rotate on 1 axis.
If I use a chain IK constraint all the joints don’t have constraints I want. And the 2 bone IK doesn’t have bones.
Any ideas how I can properly set this up? Or how I can use a combination of constraints to achieve the wanted result?
Unfortunately, the current version of the animation rigging packages doesn’t contain a “Rotation Limit” constraint… If you have the time and/or resources that could be fairly easy to build using the animation rigging API.
Otherwise, you can probably try to duplicate the leg hierarchy and use a two bone IK constraint to control it. Then, use Multi-Parent Constraint to have the Tip affect the original end bone of the original chain… and then use Multi-Rotation constraint on all of the remaining bones of the original chain and leverage the Constrained Axis options to isolate the wanted axis…
Please note this is a purely theoretical solution… I’ve never experiment it yet… But I’m confident that, using the proper order of evaluation on the rig builder component level and at (the same time) the hierarchy view level, it could be achieved…
In hope, this could offer you some sorts of solutions to start with…
I have looked at some kind of rotation limit but I dont see how to make it work with for example the chain IK. Or how else to make it work.
Would this solution end up in full IK for the entire arm? It sounds like this will mainly get you IK for the first 2 parts of the arm and then the final part not being full IK. But I can understand it the wrong way.
The result I want is similar to what is show in this video:
Will something like that ever be available by default? Or will an example be available?
UPD
I was trying to recreate insect leg movement. And I kinda did it:smile:
I set up Two Bone IK Constraint one bone earlier Tip transform.
Then placed target transform as a child of the hint transform.
Hint must be placed at the end of the leg (like tip)
Target’s position and rotation must align with the last leg’s bone.
Result is not perfect, but for now, it’s enough for me.
Hope this helps someone else
For as simple joint as finger we can just use 2 bone IK. 2 bone IK don’t need to have direct chain. You can skip the middle phalange because human and monkey finger almost always move middle middle phalange along with distal phalange. And rigging can interpolate itself for that
