raheel88 -> What you can do is to draw a series of S1=const (or S2=const) lines on the same graph. Another possibility is to draw a series of "equal height" lines (mathematically "level sets"). These are the lines you obtain by setting V(S1,S2,T) = const, and then vary the const. The result will be essentially like a 2D map of a mountain where "equal hight" lines are drawn. Finally, you could try drawing it "in perspective", i.e. drawing the 3D space on 2D, just like 3D plots do. Your function is esentially a piece of a plane in 3D space, so kinda simple to draw. Just need to find intersections with the S1 an S2 axis.