CGAL users discussion list

[Marcel <>]

After some more testing, I found that all ways to obtain a vector between two 
Point_3 seem to use the same assertion. :)
Creating a Segment_3 from the points first and then using 
Segment_3::to_vector() or Segment_3::squared_length() results in the same 
failure. 

So the Point_3 insist on not being equal but still creating a vector doesn't 
work. How can I cout a point at higher precision than one decimal place? 
Might this actually be a bug as the error message suggests?

Forgot to mention in my first post:
I'm using the Exact_predicates_exact_constructions kernel with these typedefs:

typedef Exact_predicates_exact_constructions_kernel Kernel;
typedef Polyhedron_3<Kernel>            Polyhedron;
typedef Nef_polyhedron_3<Kernel>        Nef_Polyhedron;
typedef Vector_3<Kernel>                        Vector;
typedef Point_3<Kernel>                         Point;

Greetings,
Marcel

Am 01.04.2014 um 15:58 schrieb Marcel 
<>:

> Hello!
> 
> I'm trying to implement CSG operations with Nef_polyhedra on top of a given 
> framework that uses OpenSG for rendering. Now I can get all the triangle 
> data from OpenSG, but this results in 36 vertices for a cube as every 
> corner has 3 vertices (for 3 different normals). This is not a closed mesh, 
> therefore CSG operations on the Nef_polyhedron fail.
> Despite the problems that might arise from a fixed merging threshold with 
> complex models, I was trying to merge vertices in close proximity by 
> referencing the preexisting vertex in the indices array if there is one. 
> (When iterating over the given triangles)
> 
> So, first: Is there by chance a more or less convenient method for 
> automatically merging "close" vertices?
> 
> Second, the actual problem:
> When I try to compute the distance between two vertices, an assertion fails:
> 
> CGAL/Interval_nt.h:89 "!(i>s) Variable used before being intialized (or 
> CGAL bug)"
> 
> in the last line of this snippet:
> 
> CGAL::Point a = positions->at(i); // Setting these equal manually really 
> makes them equal
> CGAL::Point b = newPoint;
> CGAL::Vector vecdiff(b, a);
> 
> I don't exactly understand what is wrong here. The points are certainly 
> close as they 'cout' as the same values. Still, they are not equal by means 
> of "a == b". (And I cross-checked by setting them to the same values.)
> 
> So, is there either a way to completely avoid doing this manually or can 
> you tell me what I am doing wrong?
> 
> Greetings,
> Marcel
> 
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