I am trying to plot contour projections of a function of 3 variables in a 3-D plot, so that I may be able to see the projection of the contours on the 3 surfaces. For example say r = x^2 + y^2 + z^2. So the contour projections on all 3 plans would be concentric circles with radius r (which is varying ofcourse). Any idea how to do this ?