CGAL users discussion list

[Philipp Moeller <>]

moogroo 
<>
 writes:

> Hello,
>
> I'm still learning the ropes with CGAL, and getting a little stuck.
>
> I am trying to copy a section of a 3D polyhedron with a Delaunay surface
> triangulation into another polyhedron.
> My starting point can be seen below:
> http://pastebin.com/nLszJ2gS http://pastebin.com/nLszJ2gS 
>
> I have essentially implicitly created, and meshed an ellipsoid and output
> this to a polyhedron.  I need to take a section of this surface such that I
> have a 2D surface that was embedded in the 3D domain. 
>
> I am getting a little confused and overwhelmed looking through the manual as
> to the best way of doing this.
> Is iterating over the vertices for the required area on the original shape
> and copying the vertex positions to the new polyhedron the way to do it?
> Or maybe using the polyhedron incremental builder to construct a new
> polyhedron from the original?

Using incremental builder should work well.

You can also destructively work on the Polyhedron [1] using the
erase_facet() and make_hole() member functions.

Either of those would be more expensive than really necessary but seem
easy to implement.

Footnotes: 
[1]  
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Polyhedron_ref/Class_Polyhedron_3.html#Cross_link_anchor_1110