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Re: AbsoluteThickness - a feature or a problem?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg39455] Re: AbsoluteThickness - a feature or a problem?
  • From: "Allan Hayes" <hay at haystack.demon.co.uk>
  • Date: Sun, 16 Feb 2003 06:14:05 -0500 (EST)
  • References: <b2kni0$1jc$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

"Vladimir Bondarenko" <vvb at mail.strace.net> wrote in message
news:b2kni0$1jc$1 at smc.vnet.net...
> Hello,
>
> The following is on a tune of Bob Hanlon BobHanlon at aol.com Fri, 14 Feb
2003 03:18:25,
> Re:  How to change thickness of curves drawn by ParametricPlot3D?
>
>
> Let us take a large enough value of the absolute thickness, say, 50.
>
>
> Needs["Graphics`ParametricPlot3D`"];
>
> ParametricPlot3D[{Cos[t], Sin[t],
>       1, {AbsoluteThickness[50], RGBColor[1, 0, 0]}}, {t, 0, 2Pi}];
>
>
>
> At the graph, the outer surface of the torus is VERY jagged.
> At the same time, the inners side of the torus is fairly smooth.
>
> Should this be construed rather as a feature or rather as a bug?
>
>
> Best wishes,
>
> Vladimir Bondarenko
> Mathematical and Production Director
> Symbolic Testing Group
>
> Web  :  http://www.CAS-testing.org/  GEMM Project (95% ready)
>
> Email:  vvb at mail.strace.net
> Voice:  (380)-652-447325 Mon-Fri 6 a.m. - 3 p.m. GMT
> ICQ  :  173050619
> Mail :  76 Zalesskaya Str, Simferopol, Crimea, Ukraine

Vladimir,
The built in function ParametricPlot3D shows this feature (no need for the
package).
The plot is of a circle at height 1, but it is made up of straight line
segmets each of which becomes a evident rectangles when thickened.
Here are two illustrations that show this up more:

    gr = ParametricPlot3D[{Cos[t], Sin[t],1, {AbsoluteThickness[50],
RGBColor[1, 0, 0]}}, {t, 0, 2Pi}, PlotPoints->6];

    pt=gr[[1,1]]

{AbsoluteThickness[50],RGBColor[1,0,0],
  Line[{{1.,0.,1},{0.309017,0.951057,1}}]}

Show[Graphics3D[pt]]


--
Allan

---------------------
Allan Hayes
Mathematica Training and Consulting
Leicester UK
hay at haystack.demon.co.uk
Voice: +44 (0)116 271 4198
Fax: +44 (0)870 164 0565







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