Hi Eric,

In the past I've done things like this by drawing the contour curves in MoI's "Top" view, in the XY plane (such that z = 0 for all the points of the contour). Then, in the "Side" or "Front" view, use the Move function (with a "perpendicular" constraint on the z axis) to move the entire contour up to the desired z elevation. Then repeat for the remaining contours.

Regards,
Steve