Unwanted curves along equator on a hollow sphere that disturb Voronoi cells


I want to create Voronoi cells on a hollow 3/4 sphere. But there are strange curves along the equator which disturb the result ---- they split the cells.

Does anyone know how to delete the curves… or to create a hollow 3/4 sphere without equator curves… or any other idea to get the correct Voronoi cells?

Thank you!

Voronoi sphere.gh (8.1 KB)
Voronoi sphere.3dm (3.3 MB)

If you just need the voronoi curves, then use Brep | Brep (BBX) component.
This will bypass the sphere seam problem.

For some reason I can’t download you Voronoi sphere.3dm file…

Hello David,

Thank you! but I need the faces of the 3d Voronoi cells. And the sphere is not just a surface. It has a thickness. Can you open this 3dm?

Voronoi sphere.3dm (3.3 MB)

The part with the faces will be shity… the whole issue comes because of the surface seam.

yeeees… is there a way to delete the seam? Or how can I draw the 3/4 sphere to avoid a seam?

voronoihalfsphere.gh (14.6 KB)

Thanks Greg! But the seam is still there… a vertical one…

Darn! Didn’t notice that. I think its just the way rhino makes sphere breps out of surfaces. What is the problem that you are having with the extra line? They still can be manipulated correctly:

I want to scale the faces of those cell. But after exploding the Brep the faces with the seam running through it will be cut

in two parts…

Have to create a script that figures out which ones are split and then joins them. I can do it later tonight, going hiking right now

Thank you so much and enjoy hiking!

Join first your splitted faces on the seams before scaling them.

Voronoi sphere_re.gh (103.2 KB)

1 Like

Yep! Almost exactly my solution

Thank you! But after exploding the edges and vertices from that seam come again…

Doesn’t matter if they are scaling correctly, no?

Hi Greg,

Yes, they’re scaling correctly.

However, what I finally need are the vertices from the scaled faces. I need those vertices to build a new mesh. Since the vertices are still on those faces it leads to the same result as when you haven’t joined them…

Here’s a screenshot of my final mesh. The red marks are from the unwanted seam.

If you don’t need a full sphere you could use that

You can avoid the seam on a sphere by using another sphere with the seam in another position:

In this solution for each voronoi cell it do a check: if there are intersection with the seam and the cell, the alternative surface is used:

Voronoi sphere_re.gh (11.2 KB)

Hi Laurent,

That’s great! Thank you! Wow, it solved all the problem with the seam!

I need to set the radius to exactly 5, but the result turns out to be somehow smaller. Do you know how I can solve this problem?