Re: planar polygon plot
- To: mathgroup at smc.vnet.net
- Subject: [mg16417] Re: planar polygon plot
- From: adam.smith at hillsdale.edu
- Date: Sat, 13 Mar 1999 02:21:36 -0500
- Organization: Deja News - The Leader in Internet Discussion
- References: <7c6fad$i0s$7@dragonfly.wolfram.com>
- Sender: owner-wri-mathgroup at wolfram.com
In article <7c6fad$i0s$7 at dragonfly.wolfram.com>,
Richard S Hsu <rhsu at U.Arizona.EDU> wrote:
> Hi,
>
> I want to plot a planar polygon in 3D with shading.
> when the polygon is concave, the shading could be wrong.
>
> For a simple example:
>
> Show[ Graphics3D[ Polygon[ { {0,0,0}, {1,0.5,0}, {2,0,0},
> {2,2,0}, {1,1.5,0}, {0,2,0} } ] ] ];
>
> I know what Mathematica is doing here, but want to know
> if there is a easy way to get correct shading for general
> 3D planar polygons.
>
> Thanks
>
>
I am not sure what you mean by the shading being off. But try changing the
order of the points. I think the input below will produce what you want. I
found it by trial and error - I don't understand why it makes a difference to
Mathematica.
Show[ Graphics3D[ Polygon[ { {1,0.5,0}, {2,0,0}, {2,2,0}, {1,1.5,0},
{0,2,0},{0,0,0} } ] ];
Adam Smith
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