Values of conic constant for conic surfaces:
K < -1 then is a hypherboloid
K = -1 then is a paraboloid
-1 < K <0 then is a prolate spheroid or ellipsoid (ellipse rotated about its major axis)
K = 0 then is a sphere
K > 0 then is a obtate spheroid (ellipse rotated about its mirror axis)
