[pstricks] behavior of \parametricplotThreeD

[Herbert Voss]

Am 30.12.2011 16:45, schrieb Nitecki, Zbigniew H.:
> I am trying to draw a hyperbola in the xy-plane, and another, similar one in the yz-plane.
> When I use \parametricplotThreeD, I get the first one, but the second ends up as a line segment on the z-axis.
>
> More precisely, the code below (trying to draw one branch of each) leads to the attached picture.  Is the problem somehow related to the fact that the first entry in the second (blue) plot is zero?
>
> \begin{pspicture}(-3,-3.5)(3,3.5)

I just realized that your function is not correct:

\listfiles
\documentclass{minimal}
\usepackage{pst-3dplot}
\pagestyle{empty}

\begin{document}

\begin{pspicture}(-8,-3.5)(3,3.5)
%\psset{Alpha=30,Beta=10}
\pstThreeDCoor
\parametricplotThreeD[algebraic](-2,2){0|t|sqrt(4*t^3+36)/3}
\parametricplotThreeD(-2,2){
0
t
t 3 exp 4 mul 36 add sqrt 3 div }

%t dup t mul 4 mul 36 add sqrt 3 div %% Your function
\end{pspicture}

\end{document}


your code needs one more mul. However, use the algebraic
mode also seen in my example, which makes live easier.

Herbert