TikZ drawing (half-dashed circles in different planes)

Question

Although I have ~10 years of LaTeX experience, I never needed any drawings.

I'm trying to make this drawing, TikZ definitely seems like the only way, but I'm really in a hurry and I just can't figure out how to do the 2 circles in different planes, half-dashed.

This is the closest I've got so far.

Answer 1

You could try something like this:

\draw (3,0) arc[x radius=3, y radius=1, start angle=0, end angle=-180];
\draw [dashed] (3,0) arc[x radius=3, y radius=1, start angle=0, end angle=180];

which provides:

Change the distances (x radius, y radius, etc.) depending on your drawing. Note that (3,0) is not the center of the arc, but it is the point the arc starts to be drawn.

Answer 2

A PSTricks solution:

\documentclass{article}

\usepackage{pstricks-add}

\def\circlecut[#1](#2,#3)#4{%
  \psellipticarc(#2,#3)(#2,0.3){180}{0}
  \psellipticarc[linestyle = dotted](#2,#3)(#2,0.3){0}{180}
  \psdot(#2,#3)
  \uput{0.07}[#1](#2,#3){\scriptsize #4}%
}

\begin{document}

\begin{pspicture}[dimen = m](-0.45,-0.3)(2.45,5.3) % boundry found manually
  \psframe(0,0)(2,3.5)
  \uput[180](0,3.5){$A$}
  \uput[0](2,3.5){$B$}
  \uput[0](2,0){$C$}
  \uput[180](0,0){$D$}
  \psline(0,3.5)(1,5)(2,3.5)
  \psdot(1,5)
  \uput[30](1,5){$V$}
  \circlecut[315](1,0){$O'$}
  \circlecut[45](1,3.5){$O$}
\end{pspicture}

\end{document}