       RE: Mathematica Animation Problem

• To: mathgroup at smc.vnet.net
• Subject: [mg35454] RE: [mg35432] Mathematica Animation Problem
• From: "David Park" <djmp at earthlink.net>
• Date: Sat, 13 Jul 2002 03:48:29 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```Tobi,

Try out the SpinShow command in the Graphics`Animation` package. There is
nothing interesting about walking around a cylindrically symmetrical
structure, so I introduced an asymmetry. Also, I got rid of the Axes and
bounding box, which I don't think look good. I also increased the
PlotPoints.

Needs["Graphics`Animation`"]

plot1 = Plot3D[ Exp[-(x^2 + 3 y^2)], {x, -2, 2}, {y, -2, 2},
PlotPoints -> 30,
PlotRange -> {{-2, 2}, {-2, 2}, {0, 1}},
SphericalRegion -> True,
Axes -> False,
Boxed -> False,
ImageSize -> 500];

SpinShow[plot1, SpinOrigin -> {0, 0, 0.5},
SpinDistance -> 5]
SelectionMove[EvaluationNotebook[], All, GeneratedCell]
FrontEndTokenExecute["OpenCloseGroup"]
FrontEndTokenExecute["SelectionAnimate"]

David Park

> From: Tobi [mailto:tofesi at web.de]
To: mathgroup at smc.vnet.net
>
> Dear all,
>
> I hope someone can give me advice concerning the following Mathematica
> (Version 4.1) problem:
>
> I am trying to produce an animation of a circular "walk" around a 3D
> plot. I get the animation, but it looks like sometimes I get nearer to
> the plot and sometimes the plot looks more distant, so that I don't
> get the impression of walking on a circle.
>
> My guess is that I have not yet understood how the options
> "ViewCenter" and "ViewPoint" work.
>
> So here is what I wrote to produce the image sequence:
>
> For [alpha = 0.0, alpha < 2 Pi, alpha = alpha + 0.1,
>   Plot3D[ Exp[-(x^2 + y^2)], {x, -2, 2}, {y, -2, 2},
>           {ViewCenter -> {0, 0, 0},
>            ViewPoint -> {5 Cos[alpha], 5 Sin[alpha], 0.5}}]]
>
> So all viewpoints should lie on a circle of radius 5 around the origin
> and with a constant height of 0.5. But the visual impression is
> different, as decribed above. Anyone knows what's wrong?
>