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同心圆柱与 tikz

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同心圆柱与 tikz

我正在尝试使用 tikz 绘制两个同心圆柱体，以显示体积随半径的变化，而高度保持不变。下面左侧的插图是第一幅图，其中高度随半径固定而变化。此代码的大部分内容借鉴自 这里。右边的插图是我有疑问的地方。

在此处输入图片描述

1) 有没有办法遮蔽两个顶部底座之间的区域？我知道如何在区域之间使用 tikz 规则对常规 2-d 插图执行此操作，但我无法完全参考这两个独立的底座。

2) 显然，这个图并不理想，那么有没有更有效的方法来生成圆柱体看起来真正同心的图？也许可以手动在外圆柱内绘制一个类似的椭圆，然后尝试放置？

MWE 是：

\documentclass[border=5pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows,snakes,backgrounds,patterns,shapes.geometric,calc}

\begin{document}

\begin{tikzpicture}[scale=1]
\node [draw, cylinder, cylinder uses custom fill, cylinder body fill=lightgray!20, 
cylinder end fill=lightgray!20, shape aspect=4, rotate=90, minimum width=3cm] (c1) at 
(0,1.8){};

\coordinate(dhtop) at ($(c1.after top)!-1*.1!(c1.before top)$);
\coordinate(dhbot) at ($(c1.before bottom)!-1*.1!(c1.after bottom)$);
\coordinate(dhlabel) at ($(dhtop)!.5!(dhbot)$);
\draw[|-|] (dhbot)--(dhtop);
\path (dhlabel) node[right, outer sep = 2pt] {$dh$};

\node [draw, cylinder, shape aspect=4, rotate=90, minimum height=4cm, minimum 
width=3cm] (c) {};

\coordinate(htop) at ($(c.before top)!-1*.1!(c.after top)$);
\coordinate(hbot) at ($(c.after bottom)!-1*.1!(c.before bottom)$);
\coordinate(hlabel) at ($(htop)!.5!(hbot)+(c.north)!.9!(c.center)$);

\draw[|-|] (hbot)--(htop);
\path (hlabel) node[left] {$h$}; %Modify height label here

\coordinate (center) at ($(c.before top)!0.5!(c.after top)$);
\filldraw (center) circle (1pt);

\coordinate (rlabel) at ($(center) !0.5!(c.after top)$);
\coordinate (rtop) at ($(center)!-1*.1!(c.after top)$);

\coordinate (rend) at ($(c.mid east)!0.5!(c.after top)$);
\draw[-, shorten >=-10] (center) -- (rend);
\path (rend) node[outer sep = 5pt, left] {$r$};
\end{tikzpicture}

\bigskip

\begin{tikzpicture}[scale=1]
\node [draw, cylinder, shape aspect=6, rotate=90, cylinder uses custom fill, cylinder 
body fill=lightgray!20, minimum height=4cm, minimum width=4cm] (c1) at (0,0){};

\coordinate(htop) at ($(c1.after top)!-1*.1!(c1.before top)$);
\coordinate(hbot) at ($(c1.before bottom)!-1*.1!(c1.after bottom)$);
\coordinate(hlabel) at ($(htop)!.5!(hbot)$);
\draw[|-|] (hbot)--(htop);
\path (hlabel) node[right, outer sep = 2pt] {$h$};

\node [draw, cylinder, shape aspect=5, rotate=90, minimum height=3.9cm, minimum 
width=3cm] (c) {};

\coordinate (center) at ($(c.before top)!0.5!(c.after top)$);
\filldraw (center) circle (1pt);

\coordinate (rlabel) at ($(center) !0.5!(c.after top)$);
\coordinate (rtop) at ($(center)!-1*.1!(c.after top)$);

\coordinate (rend) at ($(c.mid east)!0.5!(c.after top)$);
\draw[-, shorten >=-10] (center) -- (rend);
\path (rend) node[outer sep = 5pt, left] {$r$};
\end{tikzpicture}

\end{document}

答案1

在元帖子，您可以通过用阴影填充外圆，然后用背景填充内圆来为圆环添加阴影。这是您的图形尝试，可能会为您提供一个起点。

在此处输入图片描述

prologues := 3;
outputtemplate := "%j%c.eps";

beginfig(1);

path c, d, r, h; 

p = 89; q = 34;
c = fullcircle xscaled p yscaled q;
d = c scaled 1.4;

fill d withcolor .9 white;
fill c withcolor white;

forsuffixes $=c,d:
  draw $; 
  draw point 4 of $ -- subpath (4,8) of $ shifted (0,-p) -- point 0 of $;
  draw subpath (0,4) of $ shifted (0,-p) dashed withdots scaled .4;
endfor

r = origin -- point 1 of c;
draw r; label.ulft(btex $r$ etex, point 0.5 of r);
fill c scaled 1/25;

h = (point 0 of d -- point 0 of d shifted (0,-p)) shifted 20 right;
ahangle := 180; ahlength := 3;
drawdblarrow h; label.rt(btex $h$ etex, point 0.5 of h);

endfig;
end.

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