Another question, create closed polylines (lines), how to?

Hy again,

delaunay mesh was not good solution for this, but i have another question?

How to make closed polylines (regions) from lines that are exploded for example?

Replies to This Discussion

Permalink Reply by Pieter Segeren on July 14, 2015 at 10:41am

Hi Andy, you should probably look into half-edge stuff, but this was how I did it in the old days. It might suffice for your goal...

Permalink Reply by andy on July 14, 2015 at 11:49am

Hy, i think you got me wrong, with this you have to draw lines, right?

But this is non planar curves, i thought to select those lines (exploded) and from them at once create closed polylines between them or closed region, however you wanna call it.

Permalink Reply by Pieter Segeren on July 15, 2015 at 9:05am

Hi Andy - guys,
when I understood this was in 3D, I came up with a way without resorting to meshes:

Attachments:

RoofOutlineFromLines_PSG.gh, 25 KB

Permalink Reply by Matt Gaydon on July 14, 2015 at 2:49pm

Hi Andy,

New idea based on your old idea (Thread) and this idea. Its not bombproof but as you can see i have tested it on a few options. You can plug in multiple roof outlines too.

You will need:

Weaverbird : http://development.food4rhino.com/project/weaverbird?etx

Python: http://development.food4rhino.com/project/ghpython?etx

Code Attached, Hope this helps.

Matt

PS If you still need the outlines just Explode the output brep in GH and then use the Extract Wireframe and Join components to get closed loops. Guessing as you wanted surfaces before the outlines is just trying to find a way to get there so did not add it to the code.

Permalink Reply by Matt Gaydon on July 14, 2015 at 6:05pm

Sorry use this code attached I forgot when doing multiple roof the meshes would be come one mesh not one per roof. Add Disjoint mesh Component to split them up before converting them to NURBS.

Attachments:

PITCHED ROOFS 01.gh, 17 KB

Permalink Reply by andy on July 15, 2015 at 6:03am

Thanks for this, but in fact i need just outlines without mesh (nurbs). i tried that but it requires adding support egdes (lines) to create mesh, right?

Let's say something like in microstation like create region tool, it creates outlines (closed lines) when you click inside boundary of lines.

But you need to create them one by one, and it's just in 2D. It would be nice to select all lines and create those outlines (closed lines).

Image one is microstation and image two is what is created outlines but PLANAR not non planar, from non planar boundary surface, is there way to create them non planar, maybe to not create over surface?

Permalink Reply by nikos tzar on July 15, 2015 at 6:59am

Hello andy,

Following Matt's first step (creating a mesh from lines with weaverbird) you can then get the faces' outlines like this:

Permalink Reply by andy on July 15, 2015 at 9:09am

Like i said i don't want to create meshes anyway with weavebird it requiers lot of manual work for preparing. Jus to create boundary outlines...

If there is no such a way, let's take a look for maybe this then. How to project control points from planar polylines (bellow) to control polylines (abowe). The polylines abowe suits to lines above.

Permalink Reply by Matt Gaydon on July 15, 2015 at 10:07am

Hi Andy,

Pieter above has given you one option without meshes above in the thread, but your idea of projecting and moving interested me so I had a little go using some of the ideas on this thread I must admit. but No Meshes :D

It will still break if you try to build the Gable ends yet,, as points are above centre lines so adds extra intersection points.

Attachments:

PROJECTED PITCHES.gh, 19 KB

Permalink Reply by Matt Gaydon on July 15, 2015 at 9:16am

Nice Work Nikos, Did not consider looking for Mesh Merge as that would create Ngon's. Also made me realise I have not install all my plug-ins again when I went to find it.

Andy, you will find the plug-in /gha with Mesh Merge here I think:

http://www.grasshopper3d.com/forum/topics/mesh-pipe

Also how come they are non Planar, I under a Quad. etc can be not planar but not the triangle, I would look to see what you file tolerances are maybe they are to high?

Permalink Reply by nikos tzar on July 15, 2015 at 10:50am

You are right, I had forgotten this was not a native component.....

The other ideas that you and Pieter posted are briliant but I still don't get what is the manual work that andy believes is required with the mesh aproach (other than installing the needed plugins).

Permalink Reply by andy on July 15, 2015 at 12:55pm

Projected pitches (Matt) somehow works, but there is a confusion somewhere (first image).

i tried nikos step but i can't finnd mesh merge to try this, it's not under this link http://www.grasshopper3d.com/forum/topics/mesh-pipe. And what i mented under the manual work, to putt some support lines. (second image)

And third , i didn't saw at first Pieter's way, acctually i don't know how it works, those nubers how need to be set. But anyway it has the same confusion as first image (projected pitches.gh)