Inflated exoskeleton (How to ?)

Hi,

I am trying to make an inflated exoskeleton quite similar to this 3D printing by Daniel Widrig.

I am quite new to Grasshopper and would need your guidance on what components would be the most appropriate to achieve this kind of shape. Specificaly regarding:

  • the irregular nature of the grid structure (using a Voronoi grid for the moment but looking for a way to deform a regular grid (faces with 4 vertices), like in the picture)

  • the distribution of protrusions (using 3d noise for the moment)

  • the inflation of the lattices

On that matter, I have found (browsing the forum) that either Cocoon, Dendro, Exoskeleton or Skeleton Fattener could be useful but after some tests I noticed that:

  • Cocoon was too slow (marching cubes algorithm probably not appropriate for this project)
  • Dendro didn’t work well (I had issues with some curves)
  • Exoskeleton was buggy (not maintained anymore)

As a result I decided to opt for Skeleton Fattener. However I am seeing inconsistencies in the branchings and can’t seem to find a way to get clean and smooth transitions between each segment.

Help !

Inflated Exoskeleton.gh (19.0 KB)

Hi lexi,

The Fatten component is usually also my go-to for these kinds of things. The downside is that when you have lots of knots with various numbers of connections, things tend to get complex and messy. You could try to adjust the DirectionOverrides to get better results.
Maybe @DanielPiker could give you some more advice. If I remember right, he’s the developer.

Have you thought about simulating the inflation, instead of trying to get it statically?

This would be pretty straightforward with Kangaroo 2. You could start with a fattened mesh, where the staffs would have a uniform, minimum thickness (or diameter). Then you could remap your Perlin Noise values to define the inflation pressure at portions of the mesh, as well as other parameters used in the simulation. Here you have to plan ahead, how to identify the mesh portions to inflate!?
A lower noise value could for instance mean more dilation resistance or vis versa.
The simulation would also allow you to get these nice pillowy effects from Widrig’s example, which your fatten-only approach probably would not. Avoiding self-collisions are key here.
Furthermore, a by-product of simulation could be that some of the more problematic areas get relaxed or changed for the better.

Here’s a recent discussion about simulating inflation with an example:

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The best solution is Dendro, if curves worked bad, use points instead.


Inflated Exoskeleton.gh (16.2 KB)

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Thank you so much, and apologies for the late reply !

Reading both your inputs/definition was very informative.

@diff-arch, I tried to adjust the DirectionOverrides already but got the same messy result. I like the idea of simulating the inflation unfortunately I wasn’t able to get a descent result using Kangaroo2. I don’t know if that’s me not correctly tuning the components or something else but the simulation was also running very slowly (probably too many distances to check).

@laurent_delrieu I had also thougth about using points instead but was fearing that dividing the lines would produce too many points and slow down the algorithm. Turns out it runs pretty well, thank you for the demonstration.

Eventually, from my different attempts I found Cocoon to be the best at outputting consistent meshes. And unlike my previous statement, it was not that slow.


from left to right: failed inflation with Kangaroo2, Dendro, then Cocoon
Inflated Exoskeleton.gh (33.5 KB)

There is still a lot to do (how to make a distorted quad grid like in the picture, how to combine smoothed/inflated sticks and straight/not smoothed sticks) but I guess I’ll try to figure it out myself or ask for insights on a different thread.

Again, thank you for your time and your kind replies.

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