How to make surface from polylines

Replies to This Discussion

Permalink Reply by peter fotiadis on December 10, 2016 at 2:46am

If the polylines are planar use Boundary Surfaces (BS).

If not:

1. Ether create a collection of triangles (using say the polyline "center" VS each segment) and then use BS (best option for making it in real life via "modules").

2. Or patch the polylines (tricky AND freaky > good luck).

3. Or make meshes (say via Starling mesh from polyline: slStarMesh) and join them.

Permalink Reply by Victoria Desponds on December 10, 2016 at 3:09am

thank you for your reply!

Unfortunately I couldn't manage to get the shapes planar.

I guess point 2 will take quite a long time and sometimes the polygons do not have one center in the middle because they are irregular.

For your third suggestion I couldn't find this slStarMesh. In which plugin is this component?

Actually the reason why I want to have a surface is to make the lines thick (rectangle cross section), so that they look like beams to print it finally 3D. I wanted to make the surface, then offset the surface and project the lines to the surfaces and cut these beams out of the whole thing. I hope you understand what I mean (:

Permalink Reply by peter fotiadis on December 11, 2016 at 11:56pm

Well ...

slStarMesh is from Starling plug-in.

Other than that ... "thicken" the lines of the graph via ExoW (or Intra lattice)  is one way since it yields (with a general dose of Karma) liquid joins.

Warning: ExoW fails in short segments and reports "engulfing" issues (sometimes it does that with no apparent reason [to me]).

The result would be ONE mesh. "Splitting" that mesh in pieces as we would do  in real-life AEC cases (nothing to do with small demo toy models) is a bit more complicated (me? I hate meshes like my sins).

Getting rectangular "beams" is far more complex since you'll need a robust node policy (joins) including clash detection AND a way to orient the profiles to some "mean" plane (plane derived (i.e fitted) from the polyline vertices per module). The plane is supposedly useful in order to cover the module with something (glass or other) in real-life.

As Nik said: post the definition/model and we'll see if this (or that) works ... if it works, he he.

Plan B: use triangulation

Permalink Reply by peter fotiadis on December 12, 2016 at 9:54am

And these 2 ... well ... are not exactly in line with the stuff what you are after ... but they give you the gist of "thickened" line graphs:

(a) via Exoskeleton (ExoW) and ...

(b) via some other way that is frequently used in real-life (a MERO KK truss system [Google: MERO]).

The first approach yields a single mesh and the second an indicative freaky collection (V1) or a single "layer" (V2) of struts. 

Both defs require the following in order to make the thickened mesh:

Both defs are "wrong" in the sense that we very rarely use Voronoi in real-life AEC designs (unpredictable "mini" struts and the likes: a controlled proximity is way better).

Attachments:

• Voronoi_ExoW_VS_MEROKK_demo_V1.gh, 146 KB
• Voronoi_ExoW_VS_MEROKK_demo_V2.gh, 144 KB

Permalink Reply by Nik Willmore on December 11, 2016 at 12:43pm

Post the Rhino model for curious puzzle solvers to play with or you'll just get hand waving answers.