Re: Transformation of 3D Objects to 2D Parallel-projection
- To: mathgroup at smc.vnet.net
- Subject: [mg108717] Re: Transformation of 3D Objects to 2D Parallel-projection
- From: dh <dh at metrohm.com>
- Date: Mon, 29 Mar 2010 05:21:12 -0500 (EST)
- References: <hong4o$7l$1@smc.vnet.net>
Hi Peter,
the function "Normal" will change a GraphicsComplex to an expression
with coordinates given explicitely. E.g.:
v = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
GraphicsComplex[v, Polygon[{1, 2, 3, 4}]] // FullForm
gives:
GraphicsComplex[List[List[1,0],List[0,1],List[-1,0],List[0,-1]],Polygon[List[1,2,3,4]]]
but:
v = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
GraphicsComplex[v, Polygon[{1, 2, 3, 4}]] // Normal // FullForm
gives:
List[Polygon[List[List[1,0],List[0,1],List[-1,0],List[0,-1]]]]
Daniel
On 28.03.2010 13:56, Peter Breitfeld wrote:
> At school one normally uses a parallel-projection to visualize 3D
> Objects. I wrote some routines to map 3D-coordinates to 2D using the
> transformation
>
> proj[{x_,y_,z_}]:={y-x/2,z-x/2}
>
> But this doesn't work for all kind of 3D-objects. At the moment I can
> use my routines to map objects build of Point[], Line[] and Polygon[]
> primitives.
>
> My problems are: If the graphic to be mapped contains a
> GraphicsComplex, the display-options (color, thickness,...) go away.
>
> So I tried to use GeometricTransform, but it seems to me, that only
> transformations 3D->3D or 2D->2D are possible.
>
> So my question: Is it possible to have routines, which will work on any
> kind of 3D-primitives including Cuboid[], Cylinder[] etc, which will
> preserve Thickness, Color etc
>
> Thanks in advance
> Peter
>
--
Daniel Huber
Metrohm Ltd.
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Tel. +41 71 353 8585, Fax +41 71 353 8907
E-Mail:<mailto:dh at metrohm.com>
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