Hi, Folks: I have two implicit functions (hyperboloid)： sqrt((x-28)^2+(y-2)^2+(z-2)^2)-sqrt((x-20)^2+(y+20)^2+(z-6)^2) = 2 sqrt((x+15)^2+(y-2)^2+(z-2)^2)-sqrt((x-20)^2+(y+20)^2+(z-6)^2) = 10 I am able to plot these two functions through display3d, but right now I want to plot the intersection line. Anybody has comments or suggestions? Thanks a lot, James