Hi J.D.

Well, generate silhouette edges too in software; though unlike creases and
boundary edges the silhouettes are view dependent, and I am not sure
whether the hardware or software approach is superior.

I usually have access to the edge data structure of the geometries that
I create, and I algorithmically generate the outline ( outline simply
as line segments and line segments *ONLY* ) based on crease edges and
boundary edges using connectivity info. rather than hardware tricks.
Generating the crease edges is by using a recursive algorithm, but once
generated there is minimal cost to render them.

Thanks for the reference

Regards

Vaidya

>On Wed, 9 Jan 2002 09:20:37 +0100, Joachim Diepstraten 
><[EMAIL PROTECTED]> wrote:

>Hi Raj
>
>> >Does anyone know how I could get just the lines along the outermost outline
>> > of the entire polyhedron?
>>
>> What you are probably looking for are silhouette edges. Can be done
>> using a stencil buffer.
>
>Wrong. You only find outer silhouettes edges by using stencil buffer.
>
>Read Gooch et Al Paper on Interactive Technical Illustration they give
>many shots on how to extract sillhouettes (though there are some
>mistakes in the paper)
>
>The fastest method already mentioned here is to use multipass rendering
>with polygonoffset but be warned pollygonoffset behaviours very different
>on different graphic cards. ([shameless promote on] If you're interested
>in code check out the link below, it includes an NPR modul using mixed-mode
>rendering which does this [shameless promote off])
>
>EOF,
> J.D.
>
>--
>Explore SRT with the help of Java3D
>(http://wwwvis.informatik.uni-stuttgart.de/relativity/minkowski)
>(http://www.antiflash.net/java3d/relativity (mirror)
>
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