The requirement was to have the central character (a hexapod walking fortress) move around on an uneven terrain multiple elevation levels with foot placement. I looked into IK Pass feature in Unity, which seems to work only for traditional humaniod avatars. I procedurally animates the legs based on points along curves, and used raycasting to determine the ground position under the feet and modify the feet trajectories acccordingly. The solution is scalable to any number of legs. I used Unity's Custom IK for the inverse kinematics of the moving limbs.