Plot contour lines computed from data in 3D, or add them to an existing 3D (RGL) surface
contour3d(x, y, z, contourArgs=NULL, ...)Returns a list of contour lines (as in contourLines),
invisibly.
numeric vector of x values (as in contour),
or a list with components x, y and z
numeric vector of y values (as in contour)
numeric z matrix (as in contour)
list of arguments to contourLines
other arguments to lines3d
Ben Bolker