How to make a closed terrace terrain from contour curves

[wim (Wim Dekeyser)]

Hei -

@joheric

I and wonder if anyone have a recommendation or idea of how to achieve the desired result in a relatively efficient way.

To get a terraced site model, it sounds like you found the appropriate way to create that - extruding the curves to the next level. To have that work well, you need to have clean input curves. There were a lot of duplicate curve segments in your file, and a few open contours, so you need to make sure you clean that up first. When you only have closed curves, select them all and extrude them to the next level (the bottom-most level is a bit lower than the others and that needs to be scaled back then). Then you can simply BooleanUnion them into one polysurface.
(Two different contours are located at the same height and, as a result, one of them will disappear in the final result).
2021-05-05-Situationsplan_3d_Skissmodell_wd.3dm (4.7 MB)

@joheric

But, I can’t edit the extrusions, and don’t know how import more contour curves in an efficient way if I would like to make more closed terraces to make the terrain more “smooth”.

You don’t mention how you need to edit the extrusions, but to get a smooth terrain (as opposed to terraced), you could experiment with the MeshFromPoints command or use Grasshopper’s Delaunay Mesh component to create a mesh from points. As with the extrude method, you need to provide clean input for both of these workflows. A quick Grasshopper file attached…

2021-05-05-Situationsplan_3d_Skissmodell.gh (409.8 KB)
-wim