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["Amir Vaxman" <>]

Yes, I know that there is deterministic that the intersection of oriented
planes is reflex or convex, if the point of view is consistent (looking from
the positive or negative). I need to know how to compute the predicate..

Amir.

-----Original Message-----
From: 

 
[mailto:]
 On Behalf Of Mathieu
Br?dif
Sent: Tuesday, August 26, 2008 4:26 PM
To: 

Subject: Re: [cgal-discuss] Determining if the intersection between two
planes is convex

As far as I understand, this problem is easy : any 2 oriented planes,
in a non degenerate setup, may form both a  reflex or a non reflex
edge :
let say the 2 planes are x=0 and y=0 (oriented normals (1,0,0) and  (0,1,0)
),
then they can form either
- the reflex edge between the halfplanes {(0,y,z)/y>=0} and {(x,0,z)/x>=0}
- the non-reflex edge between the halfplanes {(0,y,z)/y<=0} and
{(x,0,z)/x<=0}

Mathieu

On Mon, Aug 25, 2008 at 3:59 PM, Amir Vaxman 
<>
wrote:
> Suppose I have two oriented planes in 3D, and I wish to know if the
> intersecting line between them is reflex or not (if they both were faces
of
> some polyhedron, and it was the edge between them, but I don't have any
> other edge or face available). How can I achieve that?
>
>
>
> Amir.
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