Re: Problems updating Graphics3D Polygons

• To: mathgroup at smc.vnet.net
• Subject: [mg77640] Re: Problems updating Graphics3D Polygons
• From: dh <dh at metrohm.ch>
• Date: Thu, 14 Jun 2007 05:27:24 -0400 (EDT)
• References: <f4ol3r\$6uj\$1@smc.vnet.net>

```
Hi,

Hope this helps, Daniel

chuck009 wrote:

> Hello guys.  Can you help me write a function which takes a Graphics3D object and multiplies the z-coordinate of each point of all the polygons by a ratio.  This is what I have so far but it's not working:

>

> In[473]:=

> ExpandZ[g_,ratio_]:=

>     g/.Polygon[pts_]:>Polygon[{#[[1]],#[[2]],#[[3]]*ratio}& /@pts];

>

> When I test it with this simple Graphics3D object:

>

> gobject=Graphics3D[{Polygon[{{0.,0.5,1.28},{0.,0.,1.},{0.5,0.,1.28},{0.5,

>             0.5,1.64}}],Polygon[{{

> 0.5,0.5,1.64},{0.5,0.,1.28},{1.,0.,2.71},{1.,0.5,3.49}}]}];

>

> It doesn't do anything:

>

> g2=Expand[gobject,2]

> InputForm[g2]

>

> Out[475]=

> â??Graphics3Dâ??

>

> Out[476]//InputForm=

> Graphics3D[{Polygon[{{0., 0.5, 1.28}, {0., 0., 1.},

>     {0.5, 0., 1.28}, {0.5, 0.5, 1.64}}],

>   Polygon[{{0.5, 0.5, 1.64}, {0.5, 0., 1.28},

>     {1., 0., 2.71}, {1., 0.5, 3.49}}]}]

>

> I'll keep working on it.  Thanks!

>

```

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