Delaunay Mesh

I am trying to create a mesh using point cloud data obtained from a surface that is approximately hemispherical. To create the mesh succesfully, I would need to use a hemisphere as the base surface. Previously, David Rutten had a plug-in within Rhino that allows this. Is there something equivalent in grasshopper?

I had accidentally put this post in the vb section.

Many thanks

William

Replies to This Discussion

Permalink Reply by David Rutten on January 10, 2014 at 2:25am

You could try mapping the points onto a hemisphere surface, then perform delaunay on the UV coordinates. That's how the original algorithm worked.

David Rutten

david@mcneel.com

Permalink Reply by WT4 on January 10, 2014 at 5:50am

But then the points will not be in the correct location. Or are you implying that I treat the x,y,z coordinates as r,theta,phi and therefore have the effect of 'flattening' the hemispherical set of point to allow me to do the delauney mesh and then doing a further transformation back to x,y,z.

Or have I totally misinterpreted what you are implying.

Many thanks

William

Permalink Reply by to] on January 10, 2014 at 5:58am

You use the uv to have a planar representation of your pointcloud and use this connectivitydiagram to connect your points in 3d.

In your point as you want a delaunay mesh, you decompose the flat solution, and use when you construct it again the 3dpoints

Permalink Reply by David Rutten on January 10, 2014 at 7:30am

That's correct, you'll create the Delaunay mesh in UV space, then copy the topology back into 3D space to the original points. You don't even have to use a surface to project onto, you can use maths directly. I attached a file which uses polar angles and line projections to convert the spherical points to a flat polar plot.