How to turn a polysurface into a surface and a surface to polycurve?

[_Vijay]

try like this.

UV lines on double curved surface

Your problem is caused by the curves from the DWG - small lines. These lines when used to create the surface defines its weighting irregularly (as the lines are of differing lengths) which will prevent any even distribution of curves over the surface. Instead you need to start from cleaner geometry: Firstly, single continuous curves rather than a series of smaller lines. Use these to create the surface, then rebuild the surface with uniform knots. I use Microstation to do this as Dynamo lacks t…