How to get curvature extremes (as edges) from a mesh?

Grasshopper
1

I want to make an efficient slip casting mould from a complex 3d form, like this:

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I want to make the mould in as few components as possible, Ideally 6 or even less, as I’m casting a chair in one piece:

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So how can I extract the edges between the faces with the most opposed face normals?

Thanks in advance.

2

Evaluate surface> get the normal vector> measure it’s XYZ components> then dispatch into lists of certain tolerances?

3

I had a go manually, its too manual. As I have around 10 different chair moulds to make. Also not possible in anything but lots of components because of the drafting angles.

4

IMG_20190525_090343
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5

Maybe a 3d voronoi with cells concentrically aligned with the mesh > mesh ray intersection etc…

6

First unweld with the angle tolerance set to whatever your normal difference is, then split into disjoint meshes. Both these methods are implemented in the standard mesh components if I recall. If not, they can be implemented very easily through GHPython/C#.

7

Thanks Anders, that’s a nice solution, will post my progress.

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8

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Thanks again! elegant solution. Now to subtract from some sort of bounding volumes to generate the negatives.

1 Like
9

@peregrine, where does the second component come from?

10

@diff-arch https://rhino.github.io/components/meshplus/unweldExplode.html

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