[pstricks] computed coordinates

[Michael Sharpe]

In the first case, \pstThreeDLine, like other pst-3dplot commands,  
accepts only normal coordinates. Your second example will work if (a)  
you replace the definition of \hit by taking out the !

\newcommand{\hit}[2]{#1\space 2 exp #2\space 2 exp add}

and (b) either (i) increase the main memory size (may not be easy on  
some systems, and will require you to regenerate formats), or (ii)  
reduce the number of evaluation points. (13 by 13 works for me with  
main memory size=1500000.)

Michael

On Aug 8, 2008, at 8:11 AM, Zbigniew Nitecki wrote:

> I want to use multido to draw arrows from the xy-plane to the graph  
> of z=x^2 +y^2 for a collection
> of points in the rectangle [-1.5,1.5]\times[0,1.5].  The following  
> code
> *********************************************************************************
> 		\multido{\rx=-1.5+0.12}{26}{%
> 			\multido{\ry=0+0.06}{26}{%
> 				\pstThreeDLine[arrows=->]%
> 					(\rx,\ry,0)%
> 					(!\rx\space \ry\space \rx\space 2 exp \ry\space 2 exp add)
> 			}
> 		}
> *************************************************************************************
> produces no errors, but also produces no arrows.  If I try to define  
> a function
> **************************************************************************************
> \newcommand{\hit}[2]{! #1\space 2 exp #2\space 2 exp add}	
> ****************************************************************************************
> and replace the last set of coordinates with
> *****************************************************
> 					(\rx, \ry, \hit{\rx}{\ry})
> *******************************************************
> I get the error message
> ********************************************************
> Runaway definition?
> ->/ArrowA { moveto } def /ArrowB { BeginArrow 1.  1.  scale  false  
> 0.\ETC.
> ! TeX capacity exceeded, sorry [main memory size=1500000].
>