Setting driven keys was something that I had some success with in the second year, particularly the face of the Cornelius character in the first Industry Exercises unit. Now, was going to attempt this with this feet rig. This was going to be a little more complicated than when I was merely following the tutorial, mainly because I was now working with a larger number of joints. Setting the driven keys was also going to prove whether or not the rather elaborate reverse control would work.
In order to set driven keys, I need a driver and the driven. The driver in this case would be the curve the I produced for the foot. This would both control the leg by the IK handle, and also control the natural roll and bend of the foot; thus making the animator's job easier.
Beginning with the left foot, how I did this was by selecting each of the joints of the reverse control individually, and then choosing Set Driven Key from the Animate Menu. All of the joints in the reverse control were listed as the driven, meaning that their action would be influenced by which ever component I chose to be the driver. I selected the curve and set this as the driver; this would be where the Foot Roll attribute that I mentioned in the previous post would come in to role.
I selected the Foot Roll as the attribute that would influence any attributes that I selected for the joints. In each of the joints, I selected the Rotate Z attribute to be influenced by the Foot Roll attribute. I keyed them at 0 to establish the driver and driven relation ship; next I moved the Foot Roll attributed to 10 and I lifted the the foot forward by the toe and keyed. A few of the toes had become low, so I fixed this by translating them up on the X axis and then keying them to the driver.
In order to make the foot movement more natural and not just a straight line, I keyframed the toes at 5, meaning that they will not move before the Foot Roll is set between 5 and 10. This resulted in a natural foot movement in which the ankle and ball bend first and then the toes follow.
As for the -10 of the Foot Roll, this was fairly simple. I just rotated the Base of the reverse control back and keyed them both at -10. I made the leg go pretty far back, as I would like this alien to have quite flexible joints.
Just as a recap of what I have done with the legs, here is a video of the progress that I have made so far.