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[Marcel <>]

Hello,

I've done further evaluations and noticed strange behaviour. The two points 
'a' and 'b' I mentioned in the first post do print like this: (defined as 
CGAL::Point_3<CGAL::Exact_predicates_exact_constructions_kernel>)

a: 0.5 0.5 0.5 (cout << "a: " << a)
a: 0/1 0/1 0/1 (cout << "a: " << a.x().exact() << a.y().exact() << 
a.z().exact())
b: 0.5 0.5 0.5 (cout << "b: " << b)
b: 0/1 0/1 0/1 (cout << "b: " << b.x().exact() << b.y().exact() << 
b.z().exact())

The output values are clearly not the same (despite being represented 
differently).

The values being the same for both points looks fine as the points come from 
another visual mesh that actually has vertices in the same place (which is 
the reason why I am doing this).
Still, these points insist in not being equal (a == b results in "false") and 
I cannot seem to create a vector from a to b to measure their distance. 
(Resulting in the assertion error described in the first post) At least one 
of these circumstances is however necessary to decide if I can ignore that 
vertex.

So what might cause the different values where just representation is 
different?
And why won't CGAL create a vector from a to b for me?

CGAL 3.9 (Ubuntu 12.04 - unfortunately, I couldn't find a backport of CGAL 
4.4)

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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