What is this surface called and how can I begin to make it?

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Permalink Reply by Brian Harms on December 14, 2011 at 1:22pm

Not sure it has a name but it's the same process used to make expanded metal. Looks like the photo is thick felt or something similar.

It's easy to fabricate (cut a series of offset lines in a flat material, then expand).

see: http://www.grasshopper3d.com/photo/sarsresearch10-1?xg_source=activity

much harder to model the expansion in grasshopper. Which are you trying to do?

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Permalink Reply by Anna Tomich on December 14, 2011 at 1:45pm

Grasshopper! Yeah, something so simple in real life is going to be tough to do in 3d. Do you have any suggestions? Of what to search for/how I can search it to find a tutorial? Or if you can tell me more or less how to do it. How to begin to do it.

Thank you very much for your time,

Anni

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Permalink Reply by Michael Pryor on December 14, 2011 at 1:51pm

Its actually not so hard and the last book on this page explains exactly how to do it "strip morphologies" I believe it even comes with the definition. http://www.morphogenesism.com/generative-algorithms.html

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Permalink Reply by Brian Harms on December 14, 2011 at 2:49pm

The method in the strip morphologies book is actually quite different. It relies on the use of many strips as opposed to a single flat sheet of material. Also the size of each "hole" in the image above is limited by the size of the cut in the material, and it cannot be any larger than is allowed by the cut.

Modeling the picture above in grasshopper would entail starting with a single flat surface, creating slits with user-defined spacing between them, and pulling/expanding the surface to see the result (or relaxing the surface in the case of a non-rigid material).

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Permalink Reply by Brian Harms on December 14, 2011 at 3:03pm

I haven't used kangaroo enough to know whether or not it is capable of achieving this, but that's where I would start. Otherwise, if you can't find a physics-based way to expand the material, you would have to basically fake it in grasshopper - which would be challenging, but possible (probably).

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Permalink Reply by Jacek Jaskólski on December 14, 2011 at 4:12pm

It's definitely doable, actually I'm working on something similar right now:

It's a part of an ongoing commercial work for a client, so I cannot share much (yet).

But what I can say is that kangaroo is perfect for this - some Springs and the Hinge / Bend forces are pretty much all you'd need to get it up and running.

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Permalink Reply by Brian Harms on December 14, 2011 at 4:14pm

That's great! Keep us updated (when you are allowed to :) )

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Permalink Reply by Brian Harms on December 15, 2011 at 1:53am

I know you can't share too much, but looking at that photo just makes me curious :)

I'll ask a few questions and just answer what you can.
Do you start out with a flat surface? If so can it be any user-defined shape?
Can the slices have varying lengths? Could they be curved instead of straight lines?

That's super awesome.... I really need to get into kangaroo.

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Permalink Reply by Jacek Jaskólski on December 15, 2011 at 2:09am

- in this case I start with a curve (closed or open) and offset it to produce the flat pattern of folds and cuts
- the pattern is of course parametric, so yes - length's & width's adjustable
- the simulation can be done with curved pieces, but it will run much slower, because there'll be more springs and more forces.

The basic principle is the same as in this simple example.

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Permalink Reply by Brian Harms on December 15, 2011 at 2:27am

Super cool

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Permalink Reply by Jacek Jaskólski on December 15, 2011 at 3:37pm

I just felt like making an infographic for this :)

the way I would aproach creating this form using Kangaroo:

blue - springs (outline and diagonals for each quad)

yellow - planarize force (each quad vertices)

green - hinge forces (on every shared quad edges)

red crosses - anchor points

green arrows - unary force or anchor springs (to pull the geometry)

Note that if one would start the simulation from a planar shape, inevitably some points from one strip would coincide with others so Kangaroo would merge them (ie. points A & B). In order to avoid that, the pattern would have to be tweaked a bit before running the first iteration.

Oh, and a detailed description of this project by François Roche can be found here.

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Permalink Reply by Michael Pryor on December 14, 2011 at 3:07pm

Fair enough, but maybe sometimes 3D needs to just replicate the final object, not its process, but it would be a fun task to try and recreate. I've seen some interesting similar models with sliced rubber.