CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

Juan Carlos Lopez Alfonso wrote:
> Hi all,
>
> There are any form to use 3D Alpha_Shapes with a general triangulation 
> like Triangulation_3? because Delaunay triangulation or Regular 
> triangulation move my points in order to obtain a linear approximation 
> of the original shape and I need to have a triangulation from a fix set 
> of points.

Nor Delaunay, nor Regular triangulation moves your points. It's building
a triangulation on top of your point set, so what do you mean?

> On the other hand, I have created a Delaunay Triangulation (Delaunay 
>  dt;) from a set of points and when I try to create an alpha_shape 
> (Alpha_shape_3 as(dt);) I have the following error: 
>  CGAL::Assertion_exception !!!

Did you read this?
http://www.cgal.org/FAQ.html#inexact_NT

If yes, showing some code might help giving you an answer.

Sebastien.

> Best regrads and thank in advance
> Juan Carlos