Issue populating surface with random {u,v} and with "populate geometry"

Hi everybody!

Does anybody know what algorithm is behid "populate geometry"?

I am testing populating a semi-spheric surface and with that component I don´t get more density of point at the top, which does happen evaluating the surface with random u´s and v´s.

Please find attached a screenshot of what´s going on.

Many thanks.

Cheers!

Replies to This Discussion

Permalink Reply by Sylvain Usai on July 17, 2013 at 11:46am

not sure at all but... As U&V subdivision is more dense in the top of the sphere, you are more likely to find a point there. Maybe the populate geometry component doesn't use u&v... anyone to complete?

Permalink Reply by David Rutten on July 17, 2013 at 3:16pm

The populate components use a multiple random insert approach. Basically, a number of random points is generated and the one that is furthest from any existing point is added to the collection. Then repeat until the desired number of points was added.

Picking random points on a shape (be it a mesh, curve, surface or brep) is typically quite fast, the slow bit is finding the best point. To this end I maintain a spatial octree of all points which allows me to quickly find nearest points. However even with this optimization Populate is still quite slow.

David Rutten

david@mcneel.com

Tirol, Austria

Permalink Reply by Miguel Vidal on July 25, 2013 at 10:36am