Offsetting and Scaling Facet Dome Panels

Hey guys,

I would like to generate a second surface shell for a facet dome. I need to offset the surfaces by the same distance but maintain edge geometry.

I've tried offsetting untrimmed surfaces and expanding them to find intersection lines but i feel pretty lost

I've tried a number things but have had no luck, this seems like if would be an obvious issue so I imagine it may have already been tackled. Anyone have any suggestions of point me in a right direction?

Thanks for any help, really appreciate it.

Kristian

Tags: Expand, Offset, Surface, dome, edges, facet, offset, surface

Attachments:

Forum2.jpg, 67 KB
forum.jpg, 216 KB

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Permalink Reply by Jon Mirtschin on May 13, 2012 at 10:40pm

Hi,

If you're happy with a plugin solution, StructDrawRhino has functionality to help in this area. Installation is outlined at http://www.geometrygym.com/installing

Cheers, Jon

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Permalink Reply by Kristian on May 14, 2012 at 8:45am

Thankyou for the reply Jon

I'm sorry, I wasn't clear enough in what I wanted though, I need all of the surfaces to be offset from their respective surfaces, not the edges of the surfaces,

but I need the edges of the off setted surfaces to meet to form a second, bigger shell.

In the Image below the surfaces are offset, but I need the surfaces to meet, I need a Russian Doll effect, but scaling the whole surface or moving it wont work.

ps. geogym is great, I've had it for a while

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Permalink Reply by Jon Mirtschin on May 14, 2012 at 9:03am

I see, I did misunderstand (might be my fault not yours).

Your problem is pretty interesting, effectively it's akin to shelling. Might be easier by the fact you polysurface faces have straight edges, although I think the faces might very well become non planar. I don't have an immediate answer for this but will think about it. Hopefully someone else has some good ideas.

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Permalink Reply by David Lister on May 2, 2013 at 11:12pm

Hey Jon,

I'm having this issue at the moment using weaverbird components.

http://www.grasshopper3d.com/group/weaverbird/forum/topics/non-plan...

Can you explain why the surfaces 'become' non planar when they are planar to begin seem to be simply offset?

Dave

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Permalink Reply by Jon Mirtschin on May 2, 2013 at 11:46pm

I'll retract that statement.

If you offset the planar surface, the surface must remain planar.

It should be possible to find the intersections and rebuild the planar faces, I'm a bit short on time at the moment but I will try and look at it when I can (if someone else doesn't beat me to it).

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Permalink Reply by David Lister on May 4, 2013 at 6:31pm

Haha... No problems, I won't hold you to it. I'm starting to work on it myself, but I think I'll post in this thread:

http://www.grasshopper3d.com/group/weaverbird/forum/topics/non-plan...

To keep it centralised.

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Permalink Reply by Sebastian L. on May 14, 2012 at 9:46am

Hey,
I am not sure if I get what you want but I attached sth that might help you, ... hopefully!

Attachments:

sphere_3D_voronoi_scaled.gh, 4 KB

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Permalink Reply by Kristian on May 14, 2012 at 10:38am

Hey, not quite, the surfaces are more irregular. In your example the geometry is spherical so scaling maintains relationships.

never the less thanks very much Sebastian!

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Permalink Reply by Sebastian L. on May 14, 2012 at 11:36am

hmm what about weaverbird, thicken component, maybe this helps or gives you another idea to handle the problem?

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Permalink Reply by Kristian on May 14, 2012 at 7:49pm

I used the "Weaverbird Offset mesh",which is pretty much exactly what you suggested, works like a charm, or at least as close as I will get.

Thanks very much!

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Permalink Reply by Sebastian L. on May 15, 2012 at 12:44am

You're welcome! :) Would be nice to see the final results! Good Luck!

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Permalink Reply by Kristian on May 14, 2012 at 10:35am

I've attached a sample file if anybody wants to have a go, there are a couple of attempts at scaling, moving and other quick attempts.

It might be helpful if I explain why I need this.
I have an erratic set of intersected stretched facet domes.

These surfaces will be used to generate the various layers of structure. This is why I need to know how to offset all surfaces of the dome, i need surfaces to all be equally offset, so the layers will stack without forming voids.

This is the type of geometry I have, the highlighted sections of the surface are trimmed for windows.