CGAL users discussion list

[Peter Hachenberger <>]

> > Since you started experimenting with the nary union, here is one more
> > advice. If you find a way to load and add the input polyhedra
> > in a sorted fashion, e.g., sort the smallest points of the polyhedra
> > lexicographically, the nary union will be faster.
>
> Is lexicographical ordering based on sorting on the X coordinate value
> followed by Y and Z? And should I use the minimum corner of the
> axis-aligned bounding box, or the minimum coordinate of any vertex?
The lexicographic sorting was just an example. The nary union gets faster, if the intermediate results are less complex.
So if you always unite polyhedra that are close to one another, you have a good chance that the polyhedra get
absorbed in one another. The best way to sort the polyhedra is a space-filling curve, but lexicographic sorting also
helps (no matter which coordinate is sorted first). Unfortunately, I cannot just give that to the user, because the sorting
must happen before the polyhedra are created and added to the nary union.

Peter