IsoCurves not being able to isolate U,V curves

hello everybody,

I’m fairly new to parametric design and tried to work on a grasshopper script for a gradient pattern on non rectangle surfaces. As you can see on the screenshots, the script works for a rectangular surfaces, but not for the non-rectangular surface above it.

I’m 100% sure it’s not working due to me not properly understanding the components. Anybody able to help me on this one? (22.9 KB)

The iso curve component needs a coordinate (add an MD slider) or set a point coordinate yourself - also make sure you right click the surface and reparameterize