generative modeling for Rhino
Using the Evaluate surface, given as uv the coordinates xy of a point with a range from 0 to 1 I have no trouble moving on a surface.
coordinate value of original point (between 0 to 1): length between original point and edge of the surface =
unknown coordinates of the new point copied on the curve : length between new point and edge of the surface
I hope you understand the problem better now, or else try to do a drawing of proportion.
If there are better solutions, I look forward to!