CGAL users discussion list

[Panagiotis Foteinos <>]

Since nobody has replied to you yet, I feel compelled to write to you... :)

The most common way of splitting triangles you do not want is by inserting their circumcenter. For your purposes, however, any point inside the circumdisk of a bad triangle would do the trick.

I did not understand what you are doing exactly with this list of points you are saying... Are you using your own list? If yes, you shouldn't: CGAL has its own flexible data structures. By traversing these structures, you are able to extract the vertices, edges, or triangles of the triangulation.

When it comes to the boundaries: if you do not use interior constrained segments, then make the input segments of the boundaries (that are initially known, this is your domain) constrained. CGAL offers an easy way to identify which edge is constrained or not, while you are traversing the triangles of the triangulation (for printing the mesh out). If you use interior constrained segments, a common way to identify the boundary edges is by employing flooding techniques (again you will mark the input segments as constrained). You may want to add "Colors" in this case, which will denote which edge is on the boundary or not.

The manual has everything you need...

Regards,
Panagiotis

On Fri, Dec 11, 2009 at 10:58 AM, José <> wrote:

Hi,

I have just started to use CGAL for mesh generation in my Computational
Fluid Dynamics (CFD) case. I need to generate a triangular mesh for a depth
integrated equation, so the size of the triangles depends on the local
depth. To solve this problem I generate a initial mesh
(Constrained_Delaunay_triangulation_2) using big triangles and I include all
the vertex of the triangulation into a list of points. Then I check the size
of each triangle and when the size is bigger than required, I include the
centroid of the triangle to the list and generate a new triangulation using
the points in the list. I continue this iterative process until the sizes of
all triangles fit the requirement. Can anyone suggest a better method to do
so?

Once the mesh is generated I have to write into a file the nodes and faces
of the triangulation which I have already solved. I have to write also the
segments of the triangles that are at the boundaries. The case I'm working
on is quite easy (rectangular domain) and I have solved it using the
line_walk method applied to the 4 lines defining my domain. I am afraid that
this won't work with a more complicate domain... :) Does anyone knows a more
general method?

Thanks a lot!!!

José.

--
View this message in context: http://n4.nabble.com/2D-Mesh-generation-and-triangles-at-boundaries-tp961174p961174.html
Sent from the cgal-discuss mailing list archive at Nabble.com.

--
You are currently subscribed to cgal-discuss.
To unsubscribe or access the archives, go to
https://lists-sop.inria.fr/wws/info/cgal-discuss