# [Gmsh] boolean partitioning

Jeremy Theler jeremy at seamplex.com
Tue May 23 11:22:44 CEST 2017

```Thanks for the example Christophe.
How do I apply PointsOf{} to a merged BREP?

--
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
> >
> >
> >
> >
> > _______________________________________________
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> > 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
>
>
>

```