i’m at the stage if rigging the character (lt. lou) i created for my upcoming short and oh yes, this means high brain activity. but you know what? i like it as a working rig is the portal of making your creations alive and free. or in other words: first the very tough work, then the big fun. to start the process, here’s the creation of a reverse foot system in maya:
set the bones in the following order: hip, knee, ankle, ball, toe. this is the ‘classic’ setup of a human-like leg which my character does have, even it’s quite a short one as you’ll see at later stages of my work. name your joints (i’ll do hip_jnt, knee_jnt etc.)!
now add a ik rp solver (skeleton > ik handle tool with ‘ikRPsolver’ (rp = rotate plane) as current solver; rotate plane is great as it offers a ‘twist’ option) by clicking on the hip joint and then on the ankle joint. let’s name this ik control ankle_ik.
add a single chain solver (‘ikSCSolver’, sc = single chain) from the ankle to the ball and name it ball_ik. add another sc solver between ball and toe and name it toe_ik.
it’s time to set up the reverse foot lock now: create a new series of bones with the joint tool starting a bit away from the ankle, then to the toe, back to the ball and a finishing step to the ankle. name the joints (rfFootLock_ctrl, rfToe_ctrl, etc.). these bones don’t necessarily need to be on top of the first bones, so move them a bit down if you don’t want to get confused and to see them more clearly).
parent ankle_ik to rfAnkle_ctrl, ball_ik to rfBall_ctrl etc. after these steps you should be able to control the whole foot with your rfFootLock_ctrl.
finished? not yet: add a locator in front of the knee joint, name it knee_ctrl and create a pole vector by selecting knee_ctrl first, then the ik handle ankle_ik and choosing constrain > pole vector. instead of a locator you can also use a nice curve representing a knee cap or anything which offers more visual information about the rotation about the knee cap when animating. play around with rfFootLock_ctrl to test your reverse foot lock system and to see why it’s advantageous to create such a setup: it simplifies the task of animating the leg/ feet a lot.
if you have troubles with your setup, always go through the following check points:
- did you position your joints right (do it in a side view, never in perspective!)?
- are all joints orienting the right way (every joint should orient to the following bone)?
- everything frozen (freeze transform joints in the default position)?
- naming (name your stuff so you don’t connect the wrong objects)?
some additional notes:
- when setting up the bones, be sure you don’t set them perfectly straight as this will confuse the solver (else you’d have to define an angle through ‘set preferred angle’ manually). just add a little bend and maya will set a correct ik solver.
- if you have incorrect orientations of your joints, try orient joint available at skeleton > orient joint or do it manually (which is often the best and most controlled way to correct rotations).
