Pyritohedron, Creating Solid from edges

Hi All,

I have recently created a script for a Pyritohedron, (cube that morphs to rhombic dodecahdron) however the shape is just a series of edge curces and I need to convert these curves into faces (surfaces)

http://en.wikipedia.org/wiki/Dodecahedron#mediaviewer/File:Pyritohe...

Does anyone know how I would do this?

Thanks very much

Sarah

Attachments:

1.jpg, 59 KB
2.jpg, 65 KB
20141109 Pyritohedron.gh, 40 KB

Replies to This Discussion

Permalink Reply by Arthur Mamou-Mani on November 9, 2014 at 7:44am

Hi Sarah,

Quick solution: GeometryGym Network Patch - see below, might need to ask for a student license though.

You can download it here: http://geometrygym.wordpress.com/downloads/

I hope this helps.

Arthur

Permalink Reply by Sarah Stell on November 9, 2014 at 8:22am

Thanks Arthur,

That's great - I've actually already got the licence as well!

Permalink Reply by Sarah Stell on November 22, 2014 at 8:22am

Hey Arthur,

I have been trying to create a weaverbird picture-frame effect (see attached) with the network patch component however the surfaces created seem to be too complex, and as soon as the cube deforms at all the weaverbird picture-frame disappears altogether.

Do you have any ideas how I can avoid this?

Thanks very much

Sarah

Attachments:

Permalink Reply by Sarah Stell on November 22, 2014 at 8:28am

Also I think part of the reason for this is because the faces of the shape are not all planar which means that offsetting the face boundaries and boolean difference havn't worked

Permalink Reply by Arthur Mamou-Mani on November 22, 2014 at 8:45am

Hi Sarah,

You have more than 4 vertices so meshes are confused as they can only form quads or triangles. In other words you need to design your component so that you can add vertices in the middle of all the lines and always form quads. See diagram below where I tried my own "Brep to Mesh":

Permalink Reply by Arthur Mamou-Mani on November 22, 2014 at 8:48am

Actually, nevermind, use "discontinuity" instead of deconstruct brep so that you get the four corners and ignore the mid ones :)

Permalink Reply by Sarah Stell on November 22, 2014 at 11:24am

Great thanks very much Arthur

Permalink Reply by Arthur Mamou-Mani on November 22, 2014 at 11:25am

Yayyy :) That would be a nice 3D printed lamp actually.

Permalink Reply by Andrei on November 23, 2014 at 8:18am

Hi Sarah,

Have a look at the definition I attached, basically you need to make a 'manual' pictureframe with these steps:

- get the pentagonal perimeter of each mesh face.

- offset it inwards.

- you now have 2 pentagons with 10 vertices and you can create a mesh from them.

Hope it makes sense, and I understood your question correctly.

Also a couple of notes: Scale is a lot faster than offset. and to get vertices, instead of using discontinuity which tends to be slow, use explode and cull one of the points (first or last) for closed polylines.

Best regards

JAM.d

Attachments:

20141123 Pyrithoderon - fb.gh, 20 KB

Permalink Reply by Sarah Stell on November 23, 2014 at 9:31am

Hi Andrei,

Thanks very much for getting back to me, unfortunately that didn't work, possibly because the faces of the Pyritohedrons faces aren't planar. The error message for offset is 'offset plane not a valid plane' and for construct mesh is 'insufficient vertices for a mesh'.

Is there anyway to thicken each face, scale it and then boolean difference, in the way you would use rhino?

Thanks very much for your help Andrei

Best

Sarah

Attachments:

20141123 Pyrithoderon.gh, 94 KB

Permalink Reply by Andrei on November 23, 2014 at 9:52am

Sarah,

see file attached;

you still need to use ggym or rather find a way to organize your lines into closed polylines for this to work. The example i sent is only for pentagonal faces- you can tweak it slightly to apply it to polygons with different numbers of edges - just change the faces when you construct the mesh.

offset only works for planar shapes as you well noticed, but this is why i made an alternative with scale.

Also, I don't know how relevant this is at this point, but the shape you have created is not technically a dodecahedron/pyritohedron. These need to have flat/planar faces, otherwise they are something else (irregular icositetrahedrons in your case) - basically each pentagonal face becomes a trapezoid and triangle because of the crease.

Andrei

Attachments:

20141123Pyrithoderon - fb2.gh, 94 KB

Permalink Reply by Sarah Stell on November 23, 2014 at 10:32am

Hey Andrei

Thanks very much - I'll have a look at this. I know its not technically a pyritohedron but unfortunately I haven't managed to calculate the relationship between the angle and the length of the changing side that will make the faces planar - obviously that would massively simplify all of this!

Thanks again - you've been very helpful

Sarah