[pstricks] [pst-vue3d, pst-3dplot] Meaning of Dobs and Decran

[Patrick Drechsler]

Hi,

please ignore my ignorance of the french language, but what do the
parameter "Dobs" and "Decran" mean and how do these parameters
influence things in the package "pst-vue3d"? Expecially how these
parameters influence scaling of the output is a mystery to me.

A brief look in the documentation as well as the code of pst-vue3d did
not get me any further. I only find lines such as

--8<---------------cut here---------------start------------->8---
6 matches for "Dobs" in buffer: pst-vue3d.tex
     64:\define at key[psset]{pst-vue3d}{Dobs}{\def\psk at TroisD@Dobs{#1}}
     68:    Dobs=100,Decran=10,%
    134:    /Dobs \psk at TroisD@Dobs\space def
    144:    /XpointVue Dobs Cos1Cos2 mul def
    145:    /YpointVue Dobs Sin1Cos2 mul def
    146:    /ZpointVue Dobs Sin2 mul def
2 matches for "Decran" in buffer: pst-vue3d.tex
     65:\define at key[psset]{pst-vue3d}{Decran}{\def\psk at TroisD@Ecran{#1}}
     68:    Dobs=100,Decran=10,%
--8<---------------cut here---------------end--------------->8---

I have tried to understand how Herbert included Manuel's
"\SphereThreeD" into pst-3dplot ("\pstThreeDSphere"). I have adopted
this feature for cylinders (and it appears to work), but I do not
understand how it works.

--8<---------------cut here---------------start------------->8---
\makeatletter
\def\pstThreeDCylinder{\@ifnextchar[{\pst at ThreeDCylinder}{\pst at ThreeDCylinder[]}}
\def\pst at ThreeDCylinder[#1](#2,#3,#4)#5#6{{%
  \psset{THETA=\psk at ThreeDplot@Beta,PHI=\psk at ThreeDplot@Beta,Dobs=10,Decran=10}%
  \psset{#1}%
  \pstThreeDNode(#2,#3,#4){CylinderCenter}%
  \rput(CylinderCenter){\CylindreThreeD(0,0,0){#5}{#6}}%
}\ignorespaces}
\makeatother
--8<---------------cut here---------------end--------------->8---

Thankful for any pointers,

Patrick

,----
| pst-3dplot.sty    2004/07/15 package wrapper for pst-3dplot.tex (hv)
| pstricks.sty    2005/12/19 v0.31 LaTeX wrapper for `PSTricks' (RN,HV)
| pstricks.tex    2005/12/22 v1.14 `PSTricks' (tvz)
|   xcolor.sty    2007/01/21 v2.11 LaTeX color extensions (UK)
|    color.cfg    2001/08/31 v1.1 color configuration of teTeX/TeXLive
|    dvips.def    1999/02/16 v3.0i Driver-dependant file (DPC,SPQR)
| pst-3dplot.tex    2005/02/19 v1.63 `PST-3dplot' (hv)
| pst-xkey.tex    2005/02/22 v1.5 PSTricks specialization of xkeyval (HA)
|  xkeyval.sty    2005/08/12 v2.5d package option processing (HA)
|  xkeyval.tex    2005/08/12 v2.5d key=value parser (HA)
| pst-vue3d.sty    2000/07/15 package wrapper for pst-vue3d.tex (ML)
| pst-vue3d.tex    2005/02/19 v1.63 `PST-VUE3D' (ML)
`----

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