dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Fri, Mar 16, 2012 at 09:28:41AM +0000, Garth N. Wells wrote:
> On 16 March 2012 09:17, Johan Hake <hake.dev@xxxxxxxxx> wrote:
> > Hello!
> >
> > I have implemented a new version of UnitSphere based on subdivision of an
> > initial octahedral surface mesh and tetrahedralization using the CGAL
> > framework.
> >
> > This is all fine, but CGAL uses alot of time tetrahedralizing the initial
> > surface mesh. CGAL is also doing some funny things with the surface mesh.
> >
> >  1) It subdivide the initial surface mesh, which I want to prevent. Is
> >     that possible.
> >  2) 1) results in small triangles on the surface, but large triangles
> >     in the interior. I set a tentative volume constraint based on the
> >     size of a triangle of the input mesh.
> >
> > You can try it out here:
> >
> >  bzr branch lp:~dolfin-core/dolfin/hake-trunk
> >
> >  from dolfin import *
> >  mesh = UnitSphereNew(4)
> >  # Do not try larger subdivisions than 4, at least for now.
> >
>
> Did you look at the CGAL demo for generating a mesh or a sphere:
>
>    http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Mesh_3/Chapter_main.html#Subsection_50.3.1
>
> ? It uses an implicit surface description. I has planning to add
> support for meshing geometries from implicit descriptions.

We (Johannes, Benjamin and myself) are planning to port the Netgen
Python wrappers for CSG (Constructive Solid Geometry) to DOLFIN C++
based on CGAL (which will allow boolean operations). Is this the same
thing?

--
Anders


> Garth
>
> >
> > Johan
> >
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