Grasshopper

algorithmic modeling for Rhino

# Mesh relaxation with collisions

Hi,

Sorry to ask, but is there a way to have a mesh relaxation that also forms over other objects that could be considered as collision objects.

So, the mesh relaxes, but tightens over some other object like a sphere for example?

Many thanks in advance for any help on this.

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### Replies to This Discussion

Hi Andrew,

No need to apologize, this sort of question is exactly why this forum exists.

Does this example help at all?:

https://github.com/Dan-Piker/Kangaroo-examples/blob/master/collisio...

It uses collisions between a closed solid and the vertices of the mesh which is being draped/wrapped. You can fix some anchors around the boundary and reduce the rest length of the edges to less than their start length if you want more of a wrapping effect.

Also, if you want a sort of vacuum wrap effect where the mesh actually pulls into the concavities of the solid, you can use pressure with a negative value (on a triangulated mesh).

Hi Daniel,

Thanks for the reply. Yes, that's exactly what I was trying to achieve, but in tandem with tensile springs rather than gravity.

How would I combine this with a mesh relaxation like for example I have added a collision sphere to your soap Film example (attached), how do you make the film mesh collide with the sphere?

Again, sorry for asking probably very basic questions! and thanks for your help.

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Here's an example of shrinking a mesh around some objects.

I switched the soapfilm goal for a standard length goal on the edges- the soapfilm one is only really for finding accurate minimal surfaces, and isn't so suited when collisions are involved.

I've also shown here 2 different ways of doing the collisions - if your collision geometry is actually a sphere, then you can use a 'clamplength' goal between the mesh vertices and an anchored point at the centre of your sphere, with the radius as the lower limit. This is simpler to calculate than a general solid collision, because it is just a distance check, so it's faster.

The other collision object uses the SolidPoint goal, which can take any closed solid.

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