代码

Question

我有以下生成圆柱体的代码

\documentclass[border=1cm]{standalone}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric,calc,decorations.pathmorphing,shapes,arrows,snakes,patterns}
\usepackage{amsmath}
\begin{document}
\begin{tikzpicture}[scale = 4, every node/.style={scale = 4}, mycyl/.style={cylinder, shape border rotate=90, draw, minimum width=1cm, aspect=0.25,anchor=south, text width=1cm, text height=.1cm}] 
\node [mycyl , fill=blue, minimum height=1.6cm] (bl) at (0,0) {};
\node [mycyl , minimum height=.3cm, fill = cyan] (yell) at (0,1) { };
\foreach \y in {.6, .7, .8}{
\draw[dashed, cyan] (.619,\y+.3) arc[x radius=.619cm, y radius=.154cm, start angle=0, end angle=-180];}
\end{tikzpicture}
\end{document}

导致

现在我想重复一下，但要画圆锥形状。我见过许多绘制圆锥形状的例子，这里用了一个：

\documentclass[border=2cm]{standalone}
\usepackage{tikz}
\begin{document}
    \begin{tikzpicture}
        \shade[top color=blue!40!white,opacity=0.75] (-1,0) arc (180:0:2cm and 0.5cm) -- (1,-4) -- cycle;
        \draw [](-1,0) arc (180:360:2cm and 0.5cm) -- (1,-4) -- cycle;
        \draw [](-1,0) arc (180:0:2cm and 0.5cm);
    \end{tikzpicture}
\end{document}

但是，除了圆锥形状外，我不确定如何重复上述操作。具体来说，我不确定如何绘制虚线以及如何将圆锥分成两个区域。有人能建议如何做到这一点吗？

Answer 1

这是一个糟糕的（人类的）解决方案，非常手动。

\documentclass[border=.5cm]{standalone}
\usepackage{tikz}
\begin{document}
    \begin{tikzpicture}
        \draw [fill=blue!40!white,opacity=1] (-1.99,3.98) -- (1.99,3.98) -- (0,0) -- cycle;
        \draw [fill=blue!20!white,opacity=1,] (0,4) circle (1.99cm and 0.4cm);
        \draw [fill=yellow!40!white,opacity=1] (-1.49,2.98) -- (1.49,2.98) -- (0,0) -- cycle;
        \draw [fill=yellow!20!white,opacity=1,] (0,3) circle (1.49cm and 0.3cm);
    \end{tikzpicture}
\end{document}

Answer 2

参数化和pgfplots是你的朋友。我曾经使用过

x = r cos(theta)
y = r sin(theta)
z = r

并绘制了两次锥体，0\leq z \leq 1一次是1\leq z \leq 2

% arara: pdflatex
\documentclass{standalone}

\usepackage{pgfplots}

\begin{document}

\begin{tikzpicture}
 \begin{axis}[view={60}{30}]
  \addplot3[surf,shader=flat,blue!20!white,
  samples=20,opacity=0.5,
  domain=1:2,y domain=0:2*pi,
  z buffer=sort]
  ({x * cos(deg(y))}, {x * sin(deg(y))}, {x});
    \addplot3[surf,shader=flat,blue,
  samples=20,opacity=0.5,
  domain=0:1,y domain=0:2*pi,
  z buffer=sort]
  ({x * cos(deg(y))}, {x * sin(deg(y))}, {x});
 \end{axis}
\end{tikzpicture}
\end{document}

您可以根据自己的需要选择颜色和按键。

Answer 3

其他解决方案也使用蒂克兹，但它是自动的，您只需要定义圆锥尺寸。

代码

\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{shadings,calc}

\begin{document}
    \begin{tikzpicture}
        %Cone data
        \pgfmathsetmacro{\radiush}{2};%Cone base radius
        \pgfmathsetmacro{\theight}{5}%Cone height (negative if you want a inverse cone)
        \pgfmathsetmacro{\cheightp}{.4}%Cut height in percent of cone height

        %Calculating coordinates
        \coordinate (center) at (0,0);
        \pgfmathsetmacro{\radiusv}{.2 * \radiush};
        \pgfmathsetmacro{\sradiush}{\radiush * (1 - \cheightp)};%only for right circular cone
        \pgfmathsetmacro{\sradiusv}{.2 * \sradiush};
        \coordinate (peak) at ($(center) + (0,\theight)$);
        \coordinate (vert1) at ($(center)+(\radiush,0)$);
        \coordinate (vert2) at ($(center)-(\radiush,0)$);
        \coordinate (svert1) at ($(vert1)!\cheightp!(peak)$);
        \coordinate (svert2) at ($(vert2)!\cheightp!(peak)$);

        %Drawing    
        \fill[left color=red!70,right color=red!70,middle color=red!40,shading=axis] (svert1) -- (peak) -- (svert2) arc (180:360:\sradiush cm and \sradiusv cm);
        \fill[left color=gray!70,right color=gray!70,middle color=gray!30,shading=axis] (vert1) -- (svert1) arc (0:-180:\sradiush cm and \sradiusv cm) -- (vert2) arc (180:360:\radiush cm and \radiusv cm);
        %Uncomment this for an inverted cone
        %\fill[inner color=gray!30,outer color=gray!50,shading=radial] (0,0) circle (\radiush cm and \radiusv cm);

        %Lines, \h in percent of cone height
        \foreach \h in {.38,.34,.30}{
            \pgfmathsetmacro{\rh}{\radiush * (1 - \h)}
            \pgfmathsetmacro{\rv}{.2 * \rh}
            \draw[black!70,densely dashed] ($(vert2)!\h!(peak)$) arc (180:360:\rh cm and \rv cm);
        }
    \end{tikzpicture}
\end{document}

结果

或者如果高度是负数：

如果您想绘制边框，可以使用\shadedraw而不是。\fill

有人可能可以改进代码，我只是觉得这很有趣。