CGAL users discussion list

[Mariette Yvinec <>]

Qianqian Fang wrote:
> hi
>
> In the past, I asked in this list about removing self-intersecting
> elements from triangular surface. I was recommended to use
> the surface mesher avoid repairing a bad mesh as it guarantees to
> have no self-intersecting elements.
>
> Now, I need to process a surface generated from other software,
> unfortunately, this mesh contains self-intersecting elements. So, I
> still need a program to fix this surface (and resample it to my
> desired density).
>
> Reading the documents of the Surface Mesher, I have the impression
> that it can be applied for this situation. The only difference
> is that the surface is not defined by gray-scale image, or an implicit
> function, but by a triangular surface mesh.
>
> Indeed, I can even define the surface by an implicit function, which
> returns the distance from a Point_3 to a Polyhedron_3, similar to
> the sphere case in the manual. Does this sound like a viable
> approach to you?
>
> If it may work, what I need is to find a subroutine to calculate the
> distance. I only found a squared_distance() for Point_3
> to Plane_3 in include/CGAL/squared_distance_3_2.h. I am wondering
> if a similar function to calculate Point3 to a polyhedron exists?
> if it does, can anyone show me an example how to use it?
>
> thank you
>
> Qianqian

The Surface mesher will be able to handle such a situation in a
a near future.
What is missing actually is the Polyhedral_surface_traits that can handle
surface defined as a triangle soup. Such a traits is going to be provided
in the next public release.

In the current release, you can find such a traits hidden in the polyhedron
demo, as Pierre said.  However you will have to hack a bit the code, ti 
bypass
the construction of the Polyhedron_3 which does not work with a self 
intersecting
triangular surface

--

Mariette Yvinec
Geometrica project team
INRIA  Sophia-Antipolis