[pstricks] Retrieving a 2D point from 3d

[Herbert Voss]

Am 29.06.2012 23:39, schrieb Clemens Schäfermeier:

>
> In this, I'd like to fill both plots with the z axis. Instead, the
> filling is between the end and the start of it. This is because the
> starting (respectively the end) point of one of the plots is not on the
> z axis.
> I've tried to use pscustom instead, with the "moveto" command first,
> then drawed the plot without the line, and finally, the filling. But
> that didn't work good since I'm not able to retrieve the endpoint in 2D.
> Here's the idea:
>
> \pscustom[linestyle=none]{
> \newpath
> \moveto(!
> % (0,0,\pntC) -> x'
> % (0,0,\pntC) -> y')
> \gsave
> \parametricplotThreeD[xPlotpoints=100,plotstyle=line](\pntB,\pntC)
> {0 \freqA t \pntB sub mul Sin t}
> \fill[style=tred]
> \grestore
> \closepath
> }

important is a closed path:

\documentclass{article}
\usepackage{pst-3dplot}
\usepackage{pstricks-add}

\begin{document}

\begin{pspicture}(-2,-4)(6,5)
     \def\freqA{3 }
     \def\pntB{1.5 \pstPI1 mul }
     \def\pntC{3 \pstPI1 mul }
     \pstThreeDCoor[zMax=10]
\pscustom[fillstyle=solid,fillcolor=red,opacity=0.5]{
     \pstThreeDLine(0, 0, \pntB)(3 \pntB mul RadtoDeg sin, 0, \pntB)
     \parametricplotThreeD[xPlotpoints=100,plotstyle=line](\pntB,\pntC)
     {3 t mul RadtoDeg sin 0 t}
     \pstThreeDLine(3 \pntC mul RadtoDeg sin, 0, \pntC)(0, 0, \pntC)
}
\pscustom[fillstyle=solid,fillcolor=blue,opacity=0.5]{
     \pstThreeDLine(0, 0, \pntB)(0, 0, \pntB)
 
\parametricplotThreeD[style=tgreen,xPlotpoints=100,plotstyle=line](\pntB,\pntC)
     {0 \freqA t \pntB sub mul RadtoDeg sin t}
     \pstThreeDLine(0, 0, \pntC)(0, 0, \pntC)
}
\end{pspicture}

\end{document}

Herbert