CGAL users discussion list

[Peter Hachenberger <>]

Hi Stephen,

I had a first look at that and I think it is not only a problem of the
files. I will have a deeper look into the problem, but I'm not sure
whether I have enough time for this this week. Please remind me, if you
don't here anything until Monday evening.

Peter

On Tue, 2008-01-29 at 11:41 -0800, Stephen Wong wrote:
> Hi there,
> 
>  
> 
> I have encountered a crash during execution of boolean operations on a
> data set.  The assertion is below.
> 
>  
> 
> CGAL error: assertion violation!
> 
> Expr: itl != it->second.end()
> 
> File: $(CGALROOT)\include\CGAL/Nef_3/SNC_external
> 
> _structure.h
> 
> Line: 567
> 
>  
> 
> If the assertion is ignored, a null-pointer reference occurs in
> make_twins() a few lines below that code.  I have attached the
> offending files, and a modification of the example
> “interface_polyhedron” program that demonstrates this error.  The
> kernels I have used are Cartesian<Gmpq> and
> Exact_predicates_exact_constructions_kernel.  I know the input files
> are ugly (a.off is pretty ugly), but they pass is_valid() and
> is_closed()/is_simple() tests both in Polyhedron_3 and
> Nef_polyhedron_3.
> 
>  
> 
> If anyone can provide any more details regarding how to avoid this
> kind of error, or why this is happening, I am glad to hear it!
> 
>  
> 
> Thanks,
> 
>  
> 
> Stephen
> 
>