# [Gmsh] boolean partitioning

Christophe Geuzaine cgeuzaine at ulg.ac.be
Tue May 23 23:09:14 CEST 2017

```> On 23 May 2017, at 11:22, Jeremy Theler <jeremy at seamplex.com> wrote:
>
> Thanks for the example Christophe.
> How do I apply PointsOf{} to a merged BREP?

Same thing: you could do e.g.

a() = ShapeFromFile("test.brep");
p() = PointsOf{ Volume{a()}; };

>
> --
> Jeremy Theler
> www.seamplex.com
>
>
>
> On Mon, 2017-05-22 at 20:52 +0200, Christophe Geuzaine wrote:
>>
>>
>> Here's an example, for Gmsh 3.0.2:
>>
>>
>>
>>
>> Box(1) = {-0, 0, 0, 1, 1, 1};
>>
>> p() = PointsOf{ Volume{1}; };
>> Characteristic Length{p()} = 0.2;
>>
>> Rectangle(7) = {0.4, 0.7, 0.2, 0.3, 0.3, 0};
>> Rectangle(8) = {-0.2, 0.3, 0.5, 0.3, 0.3, 0};
>> Rectangle(9) = {0.8, -0.2, 0.5, 0.3, 0.3, 0};
>> Rectangle(10) = {0.3, 0.3, 0.5, 0.3, 0.3, 0};
>>
>> b() = BooleanFragments{ Volume{1}; Delete; }{ Surface{7:10};
>> Delete; };
>>
>> p() = PointsOf{ Surface{b({1:6})}; };
>> Characteristic Length{p()} = 0.04;
>>
>>
>>
>>
>>
>>
>>> On 4 May 2017, at 12:30, Jeremy Theler <jeremy at seamplex.com> wrote:
>>>
>>>
>>>> I have found an another way to import a brep file. However I can't
>>>> understand how the characteristic sizes are applied. I want to
>>>> apply a
>>>> more dense mesh around the internal surfaces without the cost of a
>>>> field command.
>>>
>>> I don't either.
>>>
>>> But what I do is I set the characteristic length of all points to a
>>> basic lc
>>>
>>> p[] = Point "*";
>>> Characteristic Length { p[] } = lc;
>>>
>>> and then set a lower value for some of the points I want to refine
>>> around. You have to known the id of such points, though.
>>>
>>> Is there any better solution without falling back to a background
>>> field?
>>>
>>> --
>>> jeremy
>>> www.seamplex.com
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> gmsh mailing list
>>> gmsh at onelab.info
>>> http://onelab.info/mailman/listinfo/gmsh
>>
>> --
>> Prof. Christophe Geuzaine
>> University of Liege, Electrical Engineering and Computer Science
>> http://www.montefiore.ulg.ac.be/~geuzaine
>>
>> Free software: http://gmsh.info | http://getdp.info |
>> http://onelab.info
>>
>>
>>
>

--
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine

Free software: http://gmsh.info | http://getdp.info | http://onelab.info

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