Cut and Fill Illustration

[ZzzEbbs (Zachary)]

I am trying to create this illustration in grasshopper and wanted to prick some else’s brain. It is a cut and fill map for altering topography.
Screenshots show some iterations I have made so far but none have turned out so far.
The goal is to create a surface in the difference of the two sets of curves.

Image found from https://cargocollective.com/brycerwillis/Camp-Cornhusker

To use RegionDifference, I would need closed curves. So I tried that here:

I tried other methods such as loft, edge curves, ruled surface, etc.

It almost works: The “Cut” side/surface works but not the “Cut” side. Also this only works if I isolate one set of Existing + New lines. It goes bonkers if you set multiple curves.

Cut and Fill Illustration.3dm (5.2 MB) CutFill Test.gh (9.2 KB)

[diff-arch]

Do you simply want to trim the topography lines within your building outlines and solid hatch the buildings?

[ZzzEbbs (Zachary)]

No, I am trying to create the red and blue cut and fill areas from the reference photo. Either with a hatch or surface.

Here’s some more screenshots from my rhino model:

Full topo area. The blue lines are building outlines.

Each elevation line has a existing line (dashed) and a new construction line (solid). A set of these are highlighted in this screenshot.

I hadn’t thought of hating before, but I just tried it and still get the same problems.