CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

vanimurarka wrote:
> Hi,
>
> Is there a way I can query a polyhedron model to check whether a point
> exists as a vertex in the polyhedron?
nothing specific in the class.

> I looked into the documentation and could not seem to find any direct query.
> I do not really want to iterate over the whole set of vertices because this
> query needs to be done repeatedly in the algorithm I am implementing. 
>
> If there is no direct query, what are the suggestions for the shortest /
> most efficient way of obtaining this information?
>
> At present, the best I can think of is to maintain a separate HashTable of
> the vertices added to the polyhedron, where the x-y-z co-ordinate of the
> vertex is concatinated as a string to serve as the key of the HashTable.
> Then when I have a new point, I can use its co-ordinate values to query the
> HashTable. However, I might possibly run into accuracy issues.
As a geometric method, using a Kd_tree and the search member function
with a small epsilon (and an equality test for all candidates) might be 
a solution.
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Spatial_searching_ref/Class_Kd_tree.html

S.

> Thanks
>
> Vani