CGAL users discussion list

[Zesen Qian <>]

Hi Sebastien,

I think I was mistaken - I tried it again and it seems that I don't
have to do too much about the angle_bound - adjusting other parameters
would suffice to give a decent result.

However, it is indeed slow. One feature of my mesh is that it donsn't
have to be evenly sampled - some areas require more details than
others.  Can I do some trick so that those area receive extra
sampling, while other more monotone area get less, so I can save some
processing time?

Best,
Zesen

On Tue, May 22, 2018 at 10:26 AM, Zesen Qian 
<>
 wrote:
> Hi Sebastien,
>
> Thanks for this. I don't know if that's a similiar thing, but I tried
> https://doc.cgal.org/latest/Surface_mesher/
> by a distance function(with AABB_tree and side_of_triangle). Seen from
> the source code of the plugin, it's very similar.
>
> To get a decent result it's quite slow. If I set the angular bound to
> 90 degree(more than 30),  the algorithm is not garanteed to
> terminate(and indeed in my case). My mesh has some very thin layers
> that's easy  to be ignored by meshing, so I don't expect this method
> to work.
>
> What I'm now trying is simply using the "solidify" modifier in
> Blender, and fix the potential self-intersections using refining and
> outer-hull operation, and then use boolean operation with the original
> mesh to get a offseted mesh. I'm using libigl to do these tasks.
>
> Best,
> Zesen
>
> On Tue, May 22, 2018 at 9:59 AM, Sebastien Loriot (GeometryFactory)
> <>
>  wrote:
>> There is indeed nothing official in CGAL. However, in the Polyhedron
>> demo we wrote a small plugin that is meshing the distance function to a 
>> mesh
>> and the output is by construction guaranteed to be free from
>> self-intersections. However sharp features are not correctly meshed if
>> not protected.
>>
>> Go into 3D Surface Mesh Generation -> Offset meshing once having loaded
>> a polyhedron.
>>
>> Source code is here:
>> https://github.com/CGAL/cgal/blob/releases/CGAL-4.12-branch/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Offset_meshing_plugin.cpp
>>
>> HTH,
>>
>> Sebastien.
>>
>>
>> On 05/17/2018 07:44 PM, Zesen Qian wrote:
>>>
>>> Hi list,
>>>
>>> I have a triangulated, closed mesh which is free of any degeneracies.
>>> Is there any reliable way to offset this mesh? By reliable I mean the
>>> result mesh should be free of any degeneracies.
>>>
>>> I searched on Internet and there is simply not an library/program
>>> available that can do this. I guess CGAL isn't capable of this either,
>>> but I believe people on this list should be familiar with this topic
>>> and maybe offer some comments.
>>>
>>> Thank you.
>>>
>>> Best,
>>> Zesen
>>>
>>
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