I'm animating several robots for a little film I'm working on.  I have a nice walk animation completed for both robots and am now going through the age-old problem of planting their feet on the ground when the floor is visible.

I put a one-sided square the size of the foot on the ground and move the body so the foot stays on the square.  One frame at a time.   Ive also done it by looking up at the square from under the grid after I've made it slightly transparent.  both work , but is there a better, faster way to do this?

My method works fine, but it takes forever.