Notice the driven attributes are both the nodeState and the floorHiddenW0. With the LGround attribute at 0 have the nodeState at HasNoEffect and the floorHiddenW0 at 0. This will result in the ability to independently position the ankle controller. With LGround at 1 have the nodeState at Normal and the floorHiddenW0 at 1. This will put the constraint into effect and lock the CntrlLankle to the ground plane.




Do the same process for CntrlRankle using a custom attribute named RGround.

Skiing anyone?:

We are now going to take this one step further by adding in the rotation of the ground plane into the mix. This is useful for undulating terrain or if you are animating a skier/snowboarder type of character.

Select the floorHidden poly plan then the CntrlLankle and go Constrain > Normal.

The normal constraint works like an aim constraint so if the CntrlLankle flips on you check the aim vector of the normal constraint (it should be the Y axis for this example). Now rotate the floorHidden plane and notice the affect.



Link the normal constraints nodeState and weight to the LGround attribute:

Using a set driven key have the Lground attributes state (1 or 0) turn on and off the nodeState and weight of the normal constraint.



Notice the nodeState is "Blocking" since "HasNoEffect" is not supported in the normal constraint.

Creating the real ground plane:

Duplicate the floorHidden poly plane and name this new plane floor. Translate it to 0 in the Y. Freeze transformations. Use the Connection Editor to have the floor�s transformation attributes pipe directly into floorHidden�s transformation attributes.



Now hide the floorHidden plane and you�re all done!