CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

On 10/02/2013 09:06 AM, jiju peethambaran wrote:
> Hi,
>
> I'm working on a project based on 3D-Delauanay triangulation. It requires to
> delete and create certain cells from the Delaunay triangulation to achieve
> the objectives.
>
> I want to maintain the combinatorial structure to be locally valid even
> after the deletions and creations are performed for a smooth post processing
> of the Delaunay complex. When I went through the documentation, I found
> that,  the cells should have a coherent orientation and the neighboring
> indices of two adjacent cells must be reciprocating to each other. Moreover,
> all the cells should have vertices ordered in positive orientation.
>
>
> My queries are the following:
>
> 1. Do positive oriented neighboring cells will have an implicit coherent
> orientation?

You need to work at the level of the TDS documented here:
http://doc.cgal.org/latest/TDS_3/index.html


> 2. Whether all these conditions are equally applicable to infinite_cells?
> Can I deal with infinite_cells like finite_cells?
Yes in the TDS there is no nothing of finite or infinite cells

> 3. Please mention some functions which are useful in order to maintain the
> local validity of newly created and neighboring cells after one cell has
> been deleted.
I'm afraid there is none.

Sebastien.

> 4. In particular, If I delete a boundary cell (I consider only cell with one
> boundary face), I would like to create three new infinite cells attached to
> the remaining three new boundary faces. So how do I ensure the local
> validity of three new cells created?
>
> Any suggestions, comments would be highly appreciated.
>
>
> Jiju Peethambaran
>
>
>
>
> --
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> http://cgal-discuss.949826.n4.nabble.com/Deulanay-Triangulation-3-retaining-local-validity-while-deleting-cells-tp4658111.html
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