我怎样才能沿着平面添加一个圆圈？

Question

你好！我想知道如何添加一个圆圈 (x-1.5)^2+(y-1.5)^2=1.5^2，如红色所示。这是我的代码：

\documentclass{article}
\usepackage{pgfplots}
\usepackage{graphicx} 
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{tikz}
\usepackage{tikz-3dplot}
\usepackage{gensymb}
\usetikzlibrary{shapes,arrows,positioning}
\pgfplotsset{compat=1.18, width=10cm}

\begin{document}
\begin{center}


\tdplotsetmaincoords{60}{125}
\begin{tikzpicture}
        [tdplot_main_coords,
            cube/.style={very thick,black},
            axis/.style={->,blue,thick}]

    %draw the axes
    \draw[axis] (0,0,0) -- (4,0,0) node[anchor=west]{$x$};
    \draw[axis] (0,0,0) -- (0,4,0) node[anchor=west]{$y$};
    \draw[axis] (0,0,0) -- (0,0,4) node[anchor=west]{$z$};
 
    %draw the top and bottom of the cube
    \draw[cube] (0,0,0) -- (0,3,0) -- (3,3,0) -- (3,0,0) -- cycle;
    \draw[cube] (0,0,3) -- (0,3,3) -- (3,3,3) -- (3,0,3) -- cycle;
    
    %draw the edges of the cube
    \draw[cube] (0,0,0) -- (0,0,3);
    \draw[cube] (0,3,0) -- (0,3,3);
    \draw[cube] (3,0,0) -- (3,0,3);
    \draw[cube] (3,3,0) -- (3,3,3);

        
\end{tikzpicture}
\end{center}

\end{document}

Answer 1

添加以下代码行

            \draw[thick, red] (1.5, 1.5, 0)  circle (1.5);

平均能量损失

\documentclass{article}
\usepackage{pgfplots}
\usepackage{graphicx} 
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{tikz}
\usepackage{tikz-3dplot}
\usepackage{gensymb}
\usetikzlibrary{shapes,arrows,positioning}
\pgfplotsset{compat=1.18, width=10cm}

\begin{document}
    \begin{center}
        
        
        \tdplotsetmaincoords{60}{125}
        \begin{tikzpicture}
            [tdplot_main_coords,
            cube/.style={very thick,black},
            axis/.style={->,blue,thick}]
            
            %the circle
            \draw[thick, red] (1.5, 1.5, 0)  circle (1.5);

            %draw the axes
            \draw[axis] (0,0,0) -- (4,0,0) node[anchor=west]{$x$};
            \draw[axis] (0,0,0) -- (0,4,0) node[anchor=west]{$y$};
            \draw[axis] (0,0,0) -- (0,0,4) node[anchor=west]{$z$};
            
            %draw the top and bottom of the cube
            \draw[cube] (0,0,0) -- (0,3,0) -- (3,3,0) -- (3,0,0) -- cycle;
            \draw[cube] (0,0,3) -- (0,3,3) -- (3,3,3) -- (3,0,3) -- cycle;
            
            %draw the edges of the cube
            \draw[cube] (0,0,0) -- (0,0,3);
            \draw[cube] (0,3,0) -- (0,3,3);
            \draw[cube] (3,0,0) -- (3,0,3);
            \draw[cube] (3,3,0) -- (3,3,3);
            
        \end{tikzpicture}
    \end{center}
    
\end{document}

输出