在 Tikz 3d 中绘制篮子

Question

对于一些数学项目，我试图画一个篮子，如下图所示，

我已经画出篮子的一些线条，见下图，这是 MWE 之后的，但是我仍然在努力画出一些正确的阴影，主要是手柄上的阴影。我正在寻找球体部分的阴影，但到目前为止还没有找到任何东西。有人能帮忙吗？

\documentclass{standalone}
\usepackage{tikz}
\usepackage{tikz-3dplot}
\usepackage{tikz-cd}
\usepackage[]{calc}
\tdplotsetmaincoords{70}{0}
\begin{document}
    \begin{tikzpicture}[scale=5,tdplot_main_coords]
        \coordinate (O) at (0,0,0);
        \tdplotsetrotatedcoords{90}{90}{0}
        \tdplotdrawarc[fill = gray, tdplot_rotated_coords]{(O)}{1}{-90}{90}{}{}
        \tdplotdrawarc[fill = lightgray, tdplot_main_coords]{(O)}{1}{0}{360}{}{}        
        \tdplotsetrotatedcoords{-160}{90}{180}
        \tdplotdrawarc[tdplot_rotated_coords]{(0,0,.2)}{1}{-89.5}{90.5}{}{} 
        \tdplotdrawarc[tdplot_rotated_coords]{(0,0,-.2)}{1}{-89.5}{90.5}{}{}
    \end{tikzpicture}
\end{document}

Answer 1

欢迎来到 TeX.SE！！

另一种方法，使用Tiisometric view中的选项perspective钾Z 库和3d库。我把手柄做成了圆柱形，几乎没有什么区别，而且这样更简单。

像这样：

\documentclass[tikz,border=1.618mm]{standalone}
\usetikzlibrary{3d,perspective}

\begin{document}
\begin{tikzpicture}[isometric view,rotate around z=180,line cap=round,line join=round]
\def\w{0.15}                      % handle width
\pgfmathsetmacro\a{asin(\w)}      % handle angle 
\pgfmathsetmacro\r{sqrt(1-\w*\w)} % handle radius
\draw[fill=gray!30] (-45:1) arc (-45:135:1) arc (0:-180:1cm);
\draw[bottom color=gray,top color=gray!40] (0,0) circle (1);
\path[canvas is yz plane at x=-\w] (\r,0) arc (0:135:\r) coordinate (T); % tangent point
% inner handle
\draw[bottom color=gray!40] (270-\a:1) arc (270-\a:270+\a:1) 
    {[canvas is yz plane at x=\w] arc (180:135:\r) -- (T) arc (135:180:\r)};
% outer handle
\draw[fill=gray!30] (90+\a:1) arc (90+\a:90-\a:1)
    {[canvas is yz plane at x=\w] (\r,0) arc (0:135:\r) -- (T)  arc (135:0:\r)};
\end{tikzpicture}
\end{document}

Answer 2

计算视角相当简单，因此允许任意视角。

\documentclass[tikz,border=2mm]{standalone}
\usepackage{tikz-3dplot}
\tdplotsetmaincoords{70}{0}
\begin{document}
    \begin{tikzpicture}[scale=5,
        declare function={tcrit(\x)=atan2(cos(\x)*sin(\tdplotmaintheta),cos(\tdplotmaintheta));% limit of visibility
        w=.2;% width of the handle
        }]
        \pgfmathsetmacro{\myphi}{-30}% view angle
        \pgfmathsetmacro{\myalpha}{asin(w)}% angle computed from the width of the band
        \tdplotsetrotatedcoords{\myphi}{00}{0}
        \pgfmathsetmacro{\tcrit}{tcrit(\myphi)}% critical angle
        \begin{scope}[tdplot_rotated_coords,smooth,variable=\t]
            \draw[top color=black,bottom color=gray!50!black] 
                plot[domain=0:\tcrit] ({sin(\myalpha)},{cos(\myalpha)*cos(\t)},{sin(\t)}) 
                -- plot[domain=\tcrit:0] ({-sin(\myalpha)},{cos(\myalpha)*cos(\t)},{sin(\t)})
                -- plot[domain=-\myalpha:\myalpha-360]  ({sin(\t)},{cos(\t)},0);
            \draw[ball color=gray] 
                plot[domain=90+\myphi:-\myalpha+180] ({sin(\t)},{cos(\t)},0) --
                plot[domain=180:\tcrit] ({sin(\myalpha)},{cos(\myalpha)*cos(\t)},{sin(\t)}) 
                 -- plot[domain=\tcrit:180] ({-sin(\myalpha)},{cos(\myalpha)*cos(\t)},{sin(\t)})
                 -- plot[domain=180+\myalpha:270+\myphi] ({sin(\t)},{cos(\t)},0) 
                 [tdplot_screen_coords] 
                 arc[start angle=180,end angle=360,radius=1];
        \end{scope}
    \end{tikzpicture}
\end{document}

如果你使用，那么\pgfmathsetmacro{\myphi}{20}你会得到：