CGAL users discussion list

["Laurent Rineau (GeometryFactory)" <>]

On Friday 10 December 2010 15:21:08 Arun Ramasamy wrote:
> Hi,
> I'm using the AABB tree data structure to query if a polyhedron intersects
> with planes/line segments. I'm also altering the polyhedron mesh using
> Euler operators based on the results from the query. Is it possible to
> adjust the AABB tree to the changed polyhedron, without initializing it
> completely from scratch. So in the steps below:
> 
> 1. Polyhedron ph;
> 2. AABB_Tree tree(ph.facets_begin(), ph.facets_end());
> 3. result = tree.all_intersections(plane_query);
> 4. ph.euler_operation(result); //eg ph.split_edge();
> 
> After altering the polyhedron like this, can I query the AABB_Tree again
> like
> 
> 5. resultnew = tree.all_intersections(plane_query_new); //tree is not
> adjusted
> 
> If not, is there an alternative through which I can make the tree adjust
> based only on the changed part of the polyhedron.

No. The construction of the AABB tree is static. All what you can do is 
rebuild the tree, with:

  tree.rebuild(ph.facets_begin(), ph.facets_end());

after the operation #4, but that will cost the construction of a new tree.

-- 
Laurent Rineau, PhD
R&D Engineer at GeometryFactory           http://www.geometryfactory.com/
Release Manager of the CGAL Project       http://www.cgal.org/