使用 PSTricks 在表面上定位

Question

我想使用PSTricks和在表面上绘制一个点pst-solides3d。我的意思是，该点应该看起来像是附着在表面上。这意味着从不同角度看，该点不应该看起来像一个点。我的尝试如下，使用\psProjection，但它不起作用：

\documentclass{minimal}
\usepackage{pst-solides3d}

\begin{document}

\begin{pspicture}[solidmemory](-10,-10)(10,10)
\psset{
    Decran=50,
    viewpoint=25 25 15 rtp2xyz
}
\psSolid[
    object=octahedron,
    a=2,
    trunc=all,
    trunccoeff=.3333,
    fillcolor=grey!20!,
    name=my_octahedron,
    action=draw*
]
% The following draws a point.
\psSolid[
    object=point,
    definition=solidcentreface,
    args=my_octahedron 10,
    linecolor=red,
    text=X,
    pos=uc
]
% The following is my attempt to plot the same point but looking as it would be attached to the plane of the octahedron.
\psProjection[
    object=point,
    args=0 0,
    linecolor=red,
    pos=uc,
    text=H,
    plan=my_octahedron 10
]
\axesIIID*(1.5,1.45,1.4)(2.7,2,2)
\end{pspicture}

\end{document}

Answer 1

您必须先定义平面：

\documentclass[pstricks]{standalone}
\usepackage{pst-solides3d}    
\begin{document}

\begin{pspicture}[solidmemory](-4,-4)(5,5)
\psset{Decran=50,viewpoint=25 25 15 rtp2xyz}
\psSolid[object=octahedron,a=2,trunc=all,trunccoeff=.3333,
    fillcolor=gray!20!,name=my_octahedron,action=draw*]
% The following draws a point.
\psSolid[object=point,definition=solidcentreface,args=my_octahedron 10,
    linecolor=red,text=X,pos=uc]
\psSolid[object=plan,definition=solidface,args=my_octahedron 10,
    action=none,name=my_plan]% dont draw it
\psProjection[object=point,args=0 0,
    linecolor=blue,pos=uc,text=H,plan=my_plan]
\axesIIID*(1.5,1.45,1.4)(2.7,2,2)
\end{pspicture}

\end{document}

对于投影点使用

\psProjection[object=cercle,args=0 0 0.05,range=0 360,
    fillcolor=blue,fillstyle=solid,plan=my_plan]