Help: trouble with projecting crv to surface

I am having some trouble getting sidewalks crv to fit to the landscape surface layer in Rhino.

I created the landscape surface and now I am creating the sidewalks by projecting the curve of the sidewalk to the landscape base surface. From that I am extruding the sidewalks and patching the top - but I can’t get it to work precisely, the sidewalks are still floating in some places.
I have tried many different solutions throughout the day, I also increased the precision in Rhino without luck…
Do you have experience with the project or pull command with curves on a plane?

It is important to mention that I rebuild the surface layer with 1000x1000 too, it didn’t change thee precision.

pictures from twinmotion synced w rhino:

Hello - please post a file with the objects you are asking about.


Hi Pascal. Here’s the file

Hello - I think you can just extend the vertical sides of your sidewalks down through the terrain, and trim if need be - would that do what you need?