Quadratische Schleife aus zylindrischem Draht mit gleichmäßigem Querschnitt

Question

Ich versuche, eine quadratische Schleife aus dickem, zylindrischem Draht mit gleichmäßigem Querschnitt zu zeichnen, die auf dem Boden liegt, wie in angegeben Square_Loop.png. Das Plotten einer solchen Schleife in 3D als rechteckiger Rahmen mit Linien ohne Dicke scheint in PSTricks und/oder Ti recht einfach zu seinkZ. Allerdings ist es alles andere als einfach, dem Querschnitt etwas mehr Dimensionalität zu verleihen. Vielen Dank im Voraus für die Hilfe.

Answer 1

\documentclass[tikz,border=3.14mm]{standalone}
\usepackage{tikz-3dplot}
\usetikzlibrary{3d,angles,quotes}
\begin{document}
\tdplotsetmaincoords{70}{20}
\begin{tikzpicture}[tdplot_main_coords,thick]
 \draw[-stealth] (0,0,0) -- (6,0,0) node[below]{$x$};
 \draw[-stealth] (0,0,0) -- (0,-6,0) node[below right]{$y$};
 \draw[-stealth] (0,0,0) -- (0,0,4) node[left]{$z$};
 \begin{scope}[canvas is xy plane at z=0]
  \draw[rounded corners] (0,0) rectangle (2,-4);
  \draw[rounded corners] (0.2,-0.2) rectangle (1.8,-3.8);
  \node[fill,circle,inner sep=2pt,transform shape] (blob) at (1,-2){};
 \end{scope}
 \draw[dashed] (blob.center) -- (5,-2,0) coordinate(B) -- (5,-2,4) node[circle,draw,inner
 sep=1.5pt,solid,label=right:$A$](A){};
 \draw[-stealth] (blob.center) -- (A);
 \begin{scope}[canvas is xz plane at y=-2,transform shape]
  \pic[draw,angle radius=2cm,"$\alpha$",angle eccentricity=1.3] {angle=B--blob--A};
 \end{scope}
 \draw[semithick] (0,-4,0) -- (0,-4,1.5) (2,0,0) -- (2,0,1.5);
 \begin{scope}[canvas is yz plane at x=0,transform shape]
  \path (-4,1.2) -- (0,1.2) node[midway,above,transform shape=false]{$b$};
  \pgflowlevelsynccm
  \draw[stealth-stealth] (-4,1.2) -- (0,1.2);
 \end{scope} 
 \begin{scope}[canvas is xz plane at y=0,transform shape]
  \path (2,1.2) -- (0,1.2) node[midway,above,transform shape=false]{$a$};
  \pgflowlevelsynccm
  \draw[stealth-stealth] (2,1.2) -- (0,1.2);
 \end{scope} 
\end{tikzpicture}
\end{document}

Der 3D-Effekt ist mir nicht gelungen. Das ist das Beste, was mir in angemessener Zeit eingefallen ist.

\documentclass[tikz,border=3.14mm]{standalone}
\usepackage{tikz-3dplot}
\usetikzlibrary{3d,angles,quotes,calc}
\begin{document}
\tdplotsetmaincoords{70}{20}
\begin{tikzpicture}[tdplot_main_coords,thick]
 \draw[-stealth] (0,0,0) -- (6,0,0) node[below]{$x$};
 \draw[-stealth] (0,0,0) -- (0,-6,0) node[below right]{$y$};
 \draw[-stealth] (0,0,0) -- (0,0,4) node[left]{$z$};
 \begin{scope}[canvas is xy plane at z=0,transform shape]
  \draw[rounded corners] (0,0) rectangle (2,-4);
  \draw[rounded corners] (0.2,-0.2) rectangle (1.8,-3.8);
  \node[fill,circle,inner sep=2pt,transform shape] (blob) at (1,-2){};
  \begin{scope}
   \clip[rounded corners] (0,0) rectangle (2,-4) 
   (1.8,-3.8) -| (0.2,-0.2) -- (1.8,-0.2) -- cycle;
   \shade[top color=black!80,bottom color=black!70,middle color=gray!50,
   shading angle=-35] (0.3,0.2) rectangle (1.7,-0.3);
   \shade[top color=black!80,bottom color=black!70,middle color=gray!50,
   shading angle=-35] (0.3,-4.1) rectangle (1.7,-3.6);
   \shade[top color=black!80,bottom color=black!70,middle color=gray!50,
   shading angle=52] (-0.2,-0.3) rectangle (0.3,-3.7);
   \shade[top color=black!80,bottom color=black!70,middle color=gray!50,
   shading angle=52] (1.6,-0.3) rectangle (2.1,-3.7);
   \begin{scope}
    \clip (0,0) rectangle (0.3,-0.3);
    \shade[ball color=gray!70] (0.3,-0.3) circle[radius=0.3];
   \end{scope}
   \begin{scope}
    \clip (2,0) rectangle (1.7,-0.3);
    \shade[ball color=white] (1.7,-0.3) circle[radius=0.3];
   \end{scope}
   \begin{scope}
    \clip (0,-4) rectangle (0.3,-3.7);
    \shade[ball color=gray!30] (0.3,-3.7) circle[radius=0.3];
   \end{scope}
   \begin{scope}
    \clip (1.7,-4) rectangle (2,-3.7);
    \shade[ball color=white] (1.7,-3.7) circle[radius=0.3];
   \end{scope}
  \end{scope}
 \end{scope}
 \begin{scope}[tdplot_screen_coords]
 \end{scope}
 \draw[dashed] (blob.center) -- (5,-2,0) coordinate(B) -- (5,-2,4) node[circle,draw,inner
 sep=1.5pt,solid,label=right:$A$](A){};
 \draw[-stealth] (blob.center) -- (A);
 \begin{scope}[canvas is xz plane at y=-2,transform shape]
  \pic[draw,angle radius=2cm,"$\alpha$",angle eccentricity=1.3] {angle=B--blob--A};
 \end{scope}
 \draw[semithick] (0,-4,0) -- (0,-4,1.5) (2,0,0) -- (2,0,1.5);
 \begin{scope}[canvas is yz plane at x=0,transform shape]
  \path (-4,1.2) -- (0,1.2) node[midway,above,transform shape=false]{$b$};
  \pgflowlevelsynccm
  \draw[stealth-stealth] (-4,1.2) -- (0,1.2);
 \end{scope} 
 \begin{scope}[canvas is xz plane at y=0,transform shape]
  \path (2,1.2) -- (0,1.2) node[midway,above,transform shape=false]{$a$};
  \pgflowlevelsynccm
  \draw[stealth-stealth] (2,1.2) -- (0,1.2);
 \end{scope} 
\end{tikzpicture}
\end{document}