Extract xy-plane projected polyline from zone wall surface brep

[kmitotk]

I'm trying to set up a GH script to auto-generate crown moldings from zone wall surfaces.

I know I can use the border polyline of a zone to generate moldings at the perimeter of the room but when there is a room that's open to the room next to it you'd only need the moldings on the three sides of the room.

In such situation, you'd want to use the zone Wall Surface instead of the border polyline. And for that you need to extract a xy-plane projected polyline from the brep wall surfaces. I've been trying to setup a script to do this without success.

I'm completely new to GH and I'd really appreciate if someone could guide me on how to achieve this.

Thanks so much

[Laszlo Nagy]

In Grasshopper, you should be able to get the intersection lines/ curves of the BREP surface and a horizontal plane. Then you can use those intersection lines as the bases for the molding geometry.
I don't know exactly which Grasshopper Node/Component achieves this but I am pretty sure there is such a Node/Component.

[kmitotk]

Laszio, thank you for your advice! Yes, BREP/Plane does the cutting and you connect XY-Plane to it and you get the curve. You set the cutting plane height to be FL +/- 0 and you can move up the curve to the ceiling height using the height data extracted from the zone.

I'm actually setting up a script to auto-generate all the room finish elements, i.e. wall, floor, ceiling and moldings, out of a zone all at once. I've pretty much figured out and it works great except for a few gripes.

The wall finish element can be created out of the curve generated from the zone wall surface but the wall element generated won't recognize the wall openings so you'd have to manually cut out a hole at each window/door. I tried to use the morph, instead of wall, generated directly from the zone wall surface thinking the wall openings would be cut out from the resulting morph surface, but that was not the case unfortunately. I don't understand why because if I'm correct the wall openings are supposed be excluded from the zone wall surfaces.