[pstricks] Re: Right-handed coordinates in pst-3dplot

[Herbert Voss]

Joel Salomon wrote:
> On 1/11/06, Herbert Voss <LaTeX at zedat.fu-berlin.de> wrote:
> 
>>The only problem is, that you need to negate the x values by yourself.
> 
> 
> That's the rub exactly.
> 
> In terms of the matrix in tb72voss3d.pdf
> (texmf/doc/generic/pst-3dplot/doc/tb72voss3d.pdf in my MiKTeX
> installation), equations 2 & 3 (x_E = −x \cos\alpha + y \sin\alpha),
> an option "LeftHanded" could potentially negate the value.  If there's
> ever a request for left-handed coordinates, it should be simple to
> implement.

you can try it by editing the file pst-3dplot.pro

/ConvertTo2D {
   RotatePoint
   /x2D x neg Alpha cos mul y Alpha sin mul add def
   /y2D x Alpha sin mul y Alpha cos mul add neg Beta sin mul z Beta cos 
mul add def
} def


change it to

/ConvertTo2D {
   RotatePoint
   /x2D x Alpha cos mul y Alpha sin mul add def
   /y2D x neg Alpha sin mul y Alpha cos mul add neg Beta sin mul z Beta 
cos mul add def
} def


but then _all_ coordinate systems are changed.

Herbert