使用 TikZ 绘制粗糙表面

Question

我正在尝试使用 TikZ 绘制粗糙表面。这个问题 -自动生成显示粗糙表面上光扩散的图形- 解决同样的问题，并使用percusse 的这个答案我已经能够生成这个

不过，我想得到一个更像这样的图表（来源：接触表面.jpg从https://commons.wikimedia.org）

我怎样才能实现像这样的粗糙度轮廓？

代码

\documentclass[tikz,margin=3.14mm]{standalone}
\usetikzlibrary{decorations.pathmorphing}

\begin{document}
\begin{tikzpicture}

\draw[fill=green!40!black!50!white]
{decorate[decoration={random steps,segment length=0.5mm,amplitude=1pt}] %Roughness is amplitude
    {(0,0) -- ++(4,0)}} -- ++(0,-10mm) -- ++(-4cm,0) -- cycle;

\begin{scope}[yshift=0.1cm,yscale=-1]
\draw[fill=blue!40!black!50!white]
{decorate[decoration={random steps,segment length=0.5mm,amplitude=1pt}] %Roughness is amplitude
    {(0,0) -- ++(4,0)}} -- ++(0,-10mm) -- ++(-4cm,0) -- cycle;
\end{scope}    

\end{tikzpicture}
\end{document}

Answer 1

带着jiggly来自这个答案为了仅在 y 方向上产生随机性，可以使用适当的参数嵌套多个装饰，例如：

\documentclass[tikz,border=5]{standalone}
\usetikzlibrary{decorations.pathmorphing}

\pgfdeclaredecoration{jiggly}{step}
{
  \state{step}[width=+\pgfdecorationsegmentlength]
  {\pgfmathsetmacro{\delta}{rand*\pgfdecorationsegmentamplitude}
    \pgfpathlineto{
      \pgfpointadd
      {\pgfpoint{\pgfdecorationsegmentlength}{0pt}}
      {\pgfpointpolar{90-\pgfdecoratedangle}
          {\delta}}
    }
  }
  \state{final}
  {
    \pgfpathlineto{\pgfpointdecoratedpathlast}
  }
}

\begin{document}
\begin{tikzpicture}[line join=round]

\draw[fill=green!40!black!50!white]
  {decorate[decoration={jiggly, segment length=0.25,amplitude=0.25}]
  {decorate[decoration={jiggly, segment length=1,amplitude=1}]
  {decorate[decoration={jiggly, segment length=4,amplitude=4}]     
  {(0,0) -- ++(4,0)}}}} -- ++(0,-10mm) -- ++(-4cm,0) -- cycle;

\begin{scope}[yshift=0.5cm,yscale=-1]
\draw[fill=blue!40!black!50!white]
  {decorate[decoration={jiggly, segment length=0.25,amplitude=0.25}]
  {decorate[decoration={jiggly, segment length=1,amplitude=1}]
  {decorate[decoration={jiggly, segment length=4,amplitude=4}]     
  {(0,0) -- ++(4,0)}}}} -- ++(0,-10mm) -- ++(-4cm,0) -- cycle;
\end{scope}   

\end{tikzpicture}
\end{document}