Creating Multiple Surfaces from Collections of Polylines

Hi all, does anyone know how to create surfaces from a collection of curves/polylines such as in this example? I just want a surface to form within each branch whenever possible (these are building rooftops). Thanks for any tips.

Attachments:

Roofs Test 0829.gh, 11 KB
Roofs Test.3dm, 191 KB

Replies to This Discussion

Permalink Reply by Andrew M on August 30, 2016 at 1:22am

Thanks Peter, this is great and certainly a lot to soak up. It works pretty well on a variety of geometry and I'm looking forward to trying it out under more conditions!

Permalink Reply by peter fotiadis on August 30, 2016 at 1:49am

Well ...

IF ... you have CERTIFIED and VALID triangles/quads in a given line graph (and just that) and you can SWEAR that these are OK (don't blame me if not) there's another waaaaay smarter way (and rather bulletproof) to cut the mustard:

get the connectivity thingy (either via C# OR via Sandbox) out of a given line graph.

work with intersecting Lists of indices (Using the so called point to point connectivity trees). Use a HashSet (That's a "bit" crude way ... but who cares?) to ensure unique results.

do the ^$#^%$# triangles/quads as Breps by finding clusters of connected points (triads/quads).

join them > elementary my dear Watson.

See the attached that works on chaotic points solely having triads in mind (not suitable for your case as it is ... but if you dig into the code ... you'll get the gist of my meaning with regard List intersections and other freaky stuff).

Of course if you modify this for finding/making something and feed the thing with garbage > garbage is what you'll get (life sucks).

Moral: Learn C# ASAP - forget the rest.

Attachments:

Graphs_FindTriads_V1.gh, 129 KB

Permalink Reply by peter fotiadis on August 30, 2016 at 2:24am

BTW: Make a test: "triangulate" some thingy roughly describing a building. By that I mean create a line graph kinda like having the building envelope (as Brep or Mesh) and then getting the edges out of the BrepFaces or Mesh Faces. Ensure that we talking unique lines in the graph.

If the triangulation is wrong or describes wrongly the "building" then > go for a ride with a proper super-bike (what about an all black KTM RC8R?).

If the triangulation is good > then use the FindTriads def.

Permalink Reply by peter fotiadis on August 30, 2016 at 3:32am

BTW: why not higher order of pts clusters?

1. I hate meshes.

2. I hate patch

Permalink Reply by peter fotiadis on August 30, 2016 at 4:35am

BTW: And since I have a feeling that all the above sound Greek to you( (s%$!t happens) here's a demo:

An ex "building" is smashed into edges (and some are added since this public version supports only triangles, sorry but the other quite complex thingy is strictly internal).