I lock the feet of a character, then moving the body. The feet are kept in place. When I make a step, I move the locked foot using its controller.
Without the IK, animating a walk is a bit annoying, because the feet will always kinda slip.
Consider these animation keys from a different animation program that doesn't have the concept of "locks" and doesn't need it. They are position keys for the IK target of the right foot in a walk cycle (
left/right,
backward/forward and
up/down).
There's no micromanagement to it, it's pure holds and slopes, which an animator understands immediately. All you need to do to animate a "lock" is go to the frame directly before the "unlock" should happen and set a position key, creating a hold.
You don't have to keep track of something called a "lock", and you animate the motion of the end effector like you would animate anything: hold, jump forward in an arc, hold, jump forward. As for the foot staying planted, it should do that anyway as long as IK is enabled.
I believe that if the IK end effector has animatable transforms (position, rotation and scale) and an animatable IK on/off switch, it has everything. (Well, almost everything; some kind of IK chain twist control would also help so you can swing the IK chain left and right.)
". Any ideas?