CGAL users discussion list

[Stephen Wong <>]

Hi Bart,

Thanks for your help.  I have tried to implement a threshold numbertype based 
on Gmpq, as you have done.  However, when execution of Boolean operations, 
CGAL fails at non-assertions on some geometries.  Have you experienced this 
as well?  The amount of success I have had with removing "thin slabs" using 
this method is limited - most of the time, I get failures in CGAL's 
Nef_polyhedron_3.

Regards,

Stephen


-----Original Message-----
From: 

 
[mailto:]
 On Behalf Of Bart Janssens
Sent: January-21-08 11:04 PM
To: 

Subject: Re: [cgal-discuss] Boolean Operations (Nef_3) creating thin (e-16) 
slabs

On 1/21/08, Stephen Wong 
<>
 wrote:
> Is there a way for Nef_polyhedron_3 to remove very thin slabs based on a
> certain tolerance value?  Rounding the input values will not always solve
> this problem.

In K-3D, we solved this by using a custom number type, that compares
values up to a threshold. See
http://k3d.svn.sourceforge.net/viewvc/k3d/trunk/modules/booleans/threshold_number.h
for an example.
When using this approach, you may run into some failed assertions, see
http://www.k-3d.org/wiki/CGAL_Boolean_Operations for a patch to remove
the ones I encountered.

regards,

--
Bart Janssens
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