Inflation/compression of a tissue model

[Ruben_Verscheure]

Hello everyone,

I am currently working on a parametric model of a kidney and I am trying to simulate a simplified deflation process in Grasshopper.

The goal is to create a model that can transition from an inflated state (based on a CT-derived geometry) towards a compressed/deflated state.. My initial assumption was that this could be approached by creating a central skeleton of anchored points and connecting the outer surface to this skeleton using a network of springs or length constraints. The idea was that shortening these constraints would allow the outer surface to smoothly collapse towards the internal structure.

However, I am struggling to achieve a stable and realistic deformation. The current approach tends to create local distortions, mesh explosions, or unnatural folding rather than a smooth global compression of the kidney shape.

The model is a relatively clean remeshed surface, and I have access to the internal branching structure from the CT data, which I thought could potentially be useful as an internal constraint network.

Any suggestions, examples, or references would be greatly appreciated.

Thank you!

Deflating_0.02.gh (24.1 KB)

Deflate_0.02.3dm (234.3 KB)

[Joseph_Oster]

The .3dm file appears to be empty but the Rhino command ‘show’ fixes that.

[Ruben_Verscheure]

Indeed, I’ve used the weaverbird plugin and must have forgotten some things in the export of the file. Hope this version fixes it!

Deflate_0.04.3dm (210.1 KB)

[henrique.lb (Henrique Lattes Borçato)]

Hey Ruben, I couldn’t get an interesting result using negative pressure strength values. I’m not sure that actually works. Instead, I suggest using a vector to move the mesh vertices toward the ‘central skeleton’. It worked pretty well, except at one junction, where I had to add a small extra line segment to force the shrinking in the right direction.