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Re: Q about ParametricPlot3D

• To: mathgroup at smc.vnet.net
• Subject: [mg110023] Re: Q about ParametricPlot3D
• From: "David Park" <djmpark at comcast.net>
• Date: Sat, 29 May 2010 04:45:19 -0400 (EDT)

There are no definitions for most of the variables in your posted expression
so it will never work.


David Park
djmpark at comcast.net
http://home.comcast.net/~djmpark/  


From: S. B. Gray [mailto:stevebg at ROADRUNNER.COM] 

I would appreciate advice on these questions:

1. Why do I need Table in this expression:

ParametricPlot3D[Table[{(Cos[ang] xb + Sin[ang] yb)*radb + cenb,
    	  		(Cos[ang] xa + Sin[ang] ya)*rada + cena}^], {ang, 0,
2\[Pi]}, 
PlotStyle -> {Blue, Thickness[.01]}]

2. In the no-Table form that I expected to work,
  ParametricPlot3D[{(Cos[ang] xb + Sin[ang] yb)*radb + cenb,
   	  	   (Cos[ang] xa + Sin[ang] ya)*rada + cena},
{ang, 0, 2\[Pi]}, PlotStyle -> {Blue, Thickness[.01]}]

the Blue option works only for the first line and the Thickness option 
works only on the second line. (?) The first version (1.) works 
correctly but I don't know the syntax for giving each circle a different 
color. In actual use I will have a dozen or more circles and it is 
desirable to make every one have a different color.

3. In the first version I have put a ^ after "cena}" as a substitute for 
a similar symbol put there by Mathematica that's aligned with the bottom of
the 
line. I think it's a warning but I don't know what it means. The plot 
works correctly even with it.

Steve Gray