Extrude Boundary Surface from Iris Dome Scissor Structure


I’m pretty new to grasshopper. May I know how to extrude a boundary surface? I tried using Extrude but it does not seem to work.

I had intended for this grasshopper file to work like a camera aperture closing and opening for paper packaging applications.

  • How to extrude boundary surface?
  • Can I make each of the surface tangent/perpendicular to the curve of the arc such that the surfaces will not cut into one another?

iris dome with joints.gh (97.5 KB)

(Apologies, I tried to internalise data but can’t seem to do it.)

I’d greatly appreciate any help and guidance on this topic. I have been referencing from this two links to build:
Kinetic Clock
Iris Dome

I don’t have all the add-ons you have, but maybe this will help some. What I did was make a 2D surface from your boundary curves and then extrude them. The extrude direction is any normal to each surface, so I used EvalSrf to find the normal. Since all the surfaces are planar all normals point in the same direction, so I used the corner point UV = (0,0) as the input to EvalSrf.
Everything I did is at the lower right corner of the attached file.
iris dome with joints-bb1.gh (98.2 KB)

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Thank you Birk, that was immensely helpful! I learnt a lot :slight_smile:

With your help, I have progressed and am in the midst of incorporating the outer part of the packaging.

  • How do I split the outer cover such that it’s a mirrored double door open packaging?

  • I’ve added some spheres to suggest joints in the iris dome, but am not sure why the top few are missing.

  • I am working towards as the “door” prise away to reveal the iris dome, it also opens the dome.

Any help would be greatly appreciated. Much thanks!
iris dome.gh (101.8 KB)

double door box


Well I just couldn’t help myself - so I tweaked your file to simplify it and make it fit on my screen. It seems to work very well:

I’m trying to come up with a way to make the ribs 3D printable. The trick, of course, is how to design some sort of connector that would work for all of them. But that leaves the problem of how to handle their crossing points.
Maybe the ribs could be laser cut out of some thin metal or plastic sheet, and then just let them overlap at the crossing points.

I’ll take a look at your latest GH file and see if I can come up with some solutions.
iris dome with joints-bb2.gh (85.6 KB)

I didn’t understand what those spheres were for so I took them out in my previous file. But now they are back and in all the right places:
The fix for that is quite simple as you’ll see.
Your box is another matter. I"m not exactly clear on what you are wanting to do. ButI think the way to go about dealing with the box is to make each side of the box a separate piece - meaning an extruded rectangle/square surface. Do the same for each of the doors so that you can rotate each one independently. You’ll have to cut an opening in the side where the doors go, but you can do that with a Trim Surface before you extrude that particular side.
iris dome with joints-bb3.gh (86.0 KB)

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Hey Birk, thanks for being so responsive, and getting back real quick. I appreciate it!

The spheres were a temporary fix (shabby i know) because I can’t seem to work around the right type of connector to set up, on top of the question of how to prevent the ribs from intersecting one another. It seems like it remains a packaging concept at the moment, and not an actual packaging set-up.

No worries on the box, I got it somewhat figured out as you’ve suggested. I should be able to put everything together nicely.

Here’s the box file if anyone needs it for reference!
hinge box double door.gh (15.3 KB)