algorithmic modeling for Rhino

This is more or less my first try with grasshopper, and it hasn't been easy. The climb has been steep, but the payoff seems quite worth it.

I have a ton of issues with this design and hence a ton of questions. I’ll start with what I think is the biggest, although I’m guessing the solution won’t be too difficult.

I've gotten this far by studying files posted here. Some of what I have comes from copying chunks from others. Consequently I don’t entirely understand all of my own algorithm.


Although I’ll attempt to be as clear as possible, looking at this PDF  may be clearer. 



My design uses a Voronoi component. I use a Solid Intersection component to cut it to the shape of the base part.


The base part has lines delineating the different faces. As the algorithm proceedsthere’s no differentiation between the edges of the voronoi cells and the lines of the faces of the base part. So the baked part has stray lines inherited from the base part. How do I get rid of these?


Alternately, I've been trying another route using a Split Brep component. I've baked it and manually deleted all of the faces outside of the base part. I have three questions:

How do you separate the faces outside the base part from the faces inside the base part?

How do you turn the inside faces into 3D voronoi geometry

And what the hell is a brep? Is that grasshopper speak for solid body?

One final thing: I’m not married to my approach. If there is a solution that is completely different from what I’m doing and may work better, I’m very interested in hearing it.


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Comment by PGirgen on August 2, 2014 at 10:25pm

Ummm . . . because I'm not very bright.

Comment by David Rutten on August 2, 2014 at 2:20am

Why did you post this on a blog rather than the public forum. Not many people will see it here and I totally missed it until you posted a link from the 'pain points' discussion.

Comment by PGirgen on July 23, 2014 at 6:50pm

Hi Alex,

Thanks for the note. I think your suggestion of brep/brep intersection is kinda where I was heading with my alternative approach of using split brep. I've yet to figure out how to move this forward, but I'll continue to look at it. I'd love to hear any suggestions.

Comment by ng5 Alex on July 23, 2014 at 5:43pm

to your other questions.

brep is boundary representation. you can check the following link and of course grasshopper primer.

now there are ways to get rid of these by taking other route when it comes to intersecting. for example if you use brep/brep intersection from tab intersection/physical you can have as output intersection curves that don't contain the curves you don't want. let me look into it a little.

Comment by ng5 Alex on July 23, 2014 at 5:32pm


the red highlighted curves you see are the polysurface's edges. so when you intersect you voronoi with your initial polysurface, the resulting voronoi shells have the same edges locally.

so the script works ok, the ''problem'' is with your polysurface, but you will never get rid of the polysurface edges(seams) even if you rebuild surfaces that make the polysurface.





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