CGAL users discussion list

[Sebastien Loriot <>]

If you want to compute a hull, why are cavities an issue? I mean why 
don't you simply ignore them since by definition they are inside the hull.

If you really want to get an alpha for which they is not cavity, what 
you have to do is to get all the 3D cells that are not in the connected
component of the infinite vertex. Then for each cell call 
cell_handle->get_alpha() and take the max value. This will give you the
value at which all 3D cells are INTERIOR.

HTH,

Sebastien.

On 1/18/21 8:37 PM, Wiktua ( via cgal-discuss 
Mailing List) wrote:
> Hi, I've started using CGAL 3d alpha shapes recently to compute a concave
> hull of a protein. I'm struggling now to set alpha to a value where the
> protein's tunnels are not "scooped" out. I've went through the documentation
> but haven't found an answer to my question, perhaps I misunderstood some of
> the information. I'm attaching images for clarification.
> <http://cgal-discuss.949826.n4.nabble.com/file/t376261/Alpha_shape_comp.jpg>
>
> I understand that in each case I have one solid component but is there a way
> to detect such behaviour? What I'd like to do in this case is find the
> minimal alpha value between 40 and 80 where I get an alpha shape without any
> hollows/burried cavieties inside.
>
>
>
>
> --
> Sent from: http://cgal-discuss.949826.n4.nabble.com/