Help me for Evalutors

i want to create a simple mesh and edit every points where the lines itersect. By using glEvalPoint2 or glEvalcord2 i display the point but i can not get the exact coordinates(gometry) of that point how can i get that points that evaluted by evalutor
pls help me, this is very importnat for me
pls explain in detail

First, I’ve never used them yet. So…
If they are like Nurbs, you should check the function that is applied to a point when evaluated, then, you’ll be able to get the right coordinate.
So, try to get as much information as possible about them: google them or so.