[pstricks] multido

[Michael Sharpe]

You can clip in each ThreeD plane to get something that may work. You  
have to be very careful to not introduce glue which can mess up the  
spacing----that's why all the % within the \multido.

Michael

\documentclass[dvips]{article}
\usepackage{pst-3dplot}
\usepackage{pst-all}
\usepackage{fp}
\begin{document}
\psset{unit=1in}
\begin{pspicture}(-1.5,-1.5)(1.5,1.5)
\pstThreeDCoor[xMin=-2,xMax=2,yMin=-2,yMax=2,zMin=-2,zMax=2]
\multido{\nA=-1+.1}{21}{%
\FPmul\nAsq\nA\nA% x^2
\FPsub\nF{1}\nAsq% 1-x^2
\FProot\nG\nF{2}%sqrt(1-x^2)
%slices with x fixed
\begin{psclip}{\pstThreeDLine[linestyle=none](\nA,-\nG,-1)(\nA,\nG,-1) 
(\nA,\nG,1)(\nA,-\nG,1)(\nA,-\nG,-1)}%
\parametricplotThreeD[linecolor=red](-1,1){\nA\space t \nAsq\space t t  
mul sub}%
\end{psclip}%
%slices with y fixed---interchange x, y
\begin{psclip}{\pstThreeDLine[linestyle=none](-\nG,\nA,-1)(\nG,\nA,-1) 
(\nG,\nA,1)(-\nG,\nA,1)(-\nG,\nA,-1)}%
\parametricplotThreeD[linecolor=blue](-1,1){t \nA\space t t mul  \nAsq 
\space sub}%
\end{psclip}%
}
\end{pspicture}
\end{document}



On Nov 21, 2008, at 12:09 PM, Zbigniew Nitecki wrote:

> As a solution to the baby problem, this is brilliant.  But is there  
> a way to clip a \pstThreeDPlot
> or \parametricplotThreeD?
> What I really want to do is to graph a function (in my case, (x^2- 
> y^2)/2 ) over a circle (but both the above-mentioned allow only  
> graphs over a rectangle;  if I translate into a polar form to get  
> the circular domain, then the lines go radially (or are circles)  
> instead of being x-lines and y-lines.
> This is why I wanted to use the multido.
>
> Perhaps I am unclear on the function of \function in Herbert's  
> example.  I thought that it is defined as the calculation [-2(xVal) 
> +8]/[2(xVal)-2].  So where it says
> \pstVerb{/xVal \function\space def}, what is the function of  
> \function?
>