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[Peter Hachenberger <>]

There is only one type shalfedges and it includes the following handles(pointers):

class SHalfedge

{

...

SHalfedge_handle next;

SHalfedge_handle prev;

SHalfedge_handle snext;

SHalfedge_handle sprev;

...

};

The latter two pointers navigate on a sphere map. So if you have a cube and

you have the shalfedge of the sphere map of the vertex in the lower left front

corner that belongs to the lower facet of the cube, then the snext-handle points

to a shalfedge on the same sphere map that belongs to the front face of the cube.

Likewise, the sprev-handle points to a shalfedge on the same sphere map that belongs

to the left facet of the cube. The next and the prev handle both point to shalfedges

of that belong to the lower facet of the cube---on of them is on the sphere map

of the lower left back corner and the other is on the sphere map of the lower right front

corner.

Peter 

----- wrote: -----

To:
From:
Date: 03/12/2009 12:35AM
Subject: Re: [cgal-discuss] Another question regardin Nef polyhedra - shalfedges

so.. the edge-uses, are they data-typed as shalfedges? if so, then these are
"shalfedges" which are not on the spheremap, no?

Quoting Peter Hachenberger <>:

> Hi Amir,
> you got that a bit wrong. Every shalfedge is on a sphere map. SHalfedges
> occurr
> in two types of cycles in cycles around sfaces on a sphere map and in
> halffacet cycles.
> In the latter case we call the traversing of the shalfedges an edge-use.
>
> Peter
>
> -----"Amir Vaxman" <> wrote: -----
>
> To: <>
> From: "Amir Vaxman" <>
> Date: 03/11/2009 02:17PM
> Subject: [cgal-discuss] Another question regardin Nef polyhedra - shalfedges
>
>
>
>
>
>
>
>
>
> Hello,
>
>  
>
> If I understand correctly, when I traverse a halffacet
> cycle, I get a cyclic list of shalfedges. I gatherd that every other
> shalfedge
> is on the spheremap of a vertex (and the others are what is called
> â€&#65533;oriented
> edge-useâ€&#65533;). How do I know which is which?
>
>  
>
> Amir.
>
>
>
>


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