polyhedra generator

Hi guys and gals...

I was hoping someone could suggest a better approach to my problem. I want to generate random/imperfect polyhedra for fabrication of some handheld lights.

I've got a good patch for doing this using voronoi cells [see attached], but I also wanted to explore alternate forms. Currently my feeling is the voronoi cells are more like a truncated cube than an actual polyhedron.

Ideally I'd like to take regular polyhedra generated by the polyhedron rhino plugin and apply random noise to the points in order to deform them slightly, but I don't know how to approach this in rhino [or grasshopper].

Please see my work so far, and also a screenshot of some artists work I am basing my pieces on.

If anyone has some feedback, or alternate approaches for generating imperfect/random polyhedra, please let me know... I appreciate this is pretty simple work...

Many thanks in advance

Nick

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Replies to This Discussion

Permalink Reply by Julian Buhagiar on April 10, 2017 at 6:13am

voronoi isn't quite a cube, it is multi factetted and constructed by creating an infinite plane half way between two points (perpendicular to a line drawn between the two points.) The 3d cell is therefore created by the intersection of the planes. At the boundaries- where there aren't any more points, the voronoi cuts off like a cube since the cell at the edges is infinitely big.

The reason why it looks like a cube in your model is because you only have 3 points which isn't enough to define the cell you're after (4 is probably the minimum).

TIP: you can use Populate 3d to generate random points in 3d Cartesian space OR populate geometry to randomly generate points on a surface. see attached

Permalink Reply by Julian Buhagiar on April 10, 2017 at 6:24am

You should extend the boundary box to be much bigger than the sphere... this will then mean the number of points will be the number of faces, and the seed is the random generator.

Permalink Reply by Julian Buhagiar on April 10, 2017 at 6:37am

.gh attached

Attachments:

polyhedraGenerator2.gh, 8 KB

Permalink Reply by Nick Diacre on April 10, 2017 at 7:22am

this is a big improvement, mostly because of my lack of understanding of voronoi cells and the ebefit of a larger bounding box... thank you so much.

The forms generated are better, but still not 100% what I envisaged, but I think I need to work more on the variables... it's really hard to derive from a screen based polyhedra how it might work/feel physically.

Thank you for your contribution, it's loads better than my initial work!

Nick

Permalink Reply by Julian Buhagiar on April 10, 2017 at 6:54am

Permalink Reply by Laurent DELRIEU on April 10, 2017 at 7:20am

You could look at that
https://discourse.mcneel.com/t/grasshopper-and-brazil-gemstones/21875
http://www.grasshopper3d.com/forum/topics/rocks

Permalink Reply by Nick Diacre on April 10, 2017 at 7:26am

oh wow, crystal maker nails it... I shall have a tinker now... thank you for this promising link

Nick

Permalink Reply by Nick Diacre on April 10, 2017 at 8:48am

great... so much control... I think the number of faces are the key, and then just having many seeds to choose from... I am so happy with this! Thank you so much...

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