[Tex/LaTex] How to make invisible a line in TikZ

pgfplotstikz-pgf

I tried unsuccessfully to remove or to make invisible the line connecting the left wall to the first block $m_1$ . How can I do this ? I think it's an easy thing, but I don't know exactly.

The code is:

\documentclass[11pt]{article}

\usepackage{pgfplots}
\usepackage{tikz}

\usetikzlibrary{
   decorations.markings,
   decorations.pathmorphing,
   calc,
   patterns,
   positioning
}

\tikzset{
      spring/.style={thick,decorate,decoration={zigzag,pre length=0.3cm,post length=0.3cm,segment length=6}},
      blank/.style={draw=none,fill=none,pos=0.5},
      ground/.style={fill,pattern=north east lines,draw=none,minimum width=0.5cm,minimum height=0.3cm},
      damper/.style={thick,
         decoration={markings, mark connection node=dmp,
           mark=at position 0.5 with
          {
            \node (dmp) [thick,inner sep=0pt,transform shape,rotate=-90,minimum width=10pt,minimum height=3pt,draw=none] {};
            \draw [thick] ($(dmp.north east)+(2pt,0)$) -- (dmp.south east) -- (dmp.south west) -- ($(dmp.north west)+(2pt,0)$);
            \draw [thick] ($(dmp.north)+(0,-3pt)$) -- ($(dmp.north)+(0,3pt)$);
          }
          }, decorate
      },
     box/.style={draw,thick,minimum width=1cm, minimum height=1cm}
    }

\begin{document}    

\begin{figure}[tbp]
\centering
\begin{tikzpicture}[node distance=3cm]
        \node (wall) [ground, rotate=-90, minimum width=2cm] {};
        \node (M1) [box, right=of wall.north] {$m_1$};
        \node (M2) [box,right=of M1,label=below:$f$] {$m_2$};

        \draw (wall.north east) -- (wall.north west);
        \draw [spring] (wall.north) -- (M1) node[blank,above,yshift=1mm] {};
        \draw (wall.20) -- (wall.20 -| M1.west) coordinate (d1);

        \draw [spring] (M1) -- (M2) node[blank,above,yshift=1mm] {} ;
        \draw [damper] (d1-|M1.east) -- (d1 -| M2.west);

        \node (wall2) [ground, right=of M2, anchor=north,rotate=90,minimum width=2cm] {};
        \draw [spring] (M2) -- (wall2) node[blank,above,yshift=1mm] {};
        \draw [damper] (d1-|M2.east) -- (d1 -| wall2.north);
\end{tikzpicture}
\end{figure}
\end{document}

The output is:

Best Answer

Replace \draw by \path:

\documentclass[11pt]{article}

\usepackage{pgfplots}
\usepackage{tikz}

\usetikzlibrary{
   decorations.markings,
   decorations.pathmorphing,
   calc,
   patterns,
   positioning
}

\tikzset{
      spring/.style={thick,decorate,decoration={zigzag,pre length=0.3cm,post length=0.3cm,segment length=6}},
      blank/.style={draw=none,fill=none,pos=0.5},
      ground/.style={fill,pattern=north east lines,draw=none,minimum width=0.5cm,minimum height=0.3cm},
      damper/.style={thick,
         decoration={markings, mark connection node=dmp,
           mark=at position 0.5 with
          {
            \node (dmp) [thick,inner sep=0pt,transform shape,rotate=-90,minimum width=10pt,minimum height=3pt,draw=none] {};
            \draw [thick] ($(dmp.north east)+(2pt,0)$) -- (dmp.south east) -- (dmp.south west) -- ($(dmp.north west)+(2pt,0)$);
            \draw [thick] ($(dmp.north)+(0,-3pt)$) -- ($(dmp.north)+(0,3pt)$);
          }
          }, decorate
      },
     box/.style={draw,thick,minimum width=1cm, minimum height=1cm}
    }

\begin{document}    

\begin{figure}[tbp]
\centering
\begin{tikzpicture}[node distance=3cm]
        \node (wall) [ground, rotate=-90, minimum width=2cm] {};
        \node (M1) [box, right=of wall.north] {$m_1$};
        \node (M2) [box,right=of M1,label=below:$f$] {$m_2$};

        \draw (wall.north east) -- (wall.north west);
        \draw [spring] (wall.north) -- (M1) node[blank,above,yshift=1mm] {};
        \path (wall.20) -- (wall.20 -| M1.west) coordinate (d1);

        \draw [spring] (M1) -- (M2) node[blank,above,yshift=1mm] {} ;
        \draw [damper] (d1-|M1.east) -- (d1 -| M2.west);

        \node (wall2) [ground, right=of M2, anchor=north,rotate=90,minimum width=2cm] {};
        \draw [spring] (M2) -- (wall2) node[blank,above,yshift=1mm] {};
        \draw [damper] (d1-|M2.east) -- (d1 -| wall2.north);
\end{tikzpicture}
\end{figure}
\end{document}

Related Solutions

[Tex/LaTex] Rotate a node but not its content: the case of the ellipse decoration

The source of the difficulty is that ellipses are constructed in a particular way in TikZ. They are paths that start from the x-axis and proceed counter-clockwise around their centre. The vast majority of the time, the exact parametrisation doesn't matter. You appear to have found the one situation where it does!

In the actual question, you only want to be able to mirror the ellipse, and so draw it starting from the negative x-axis (the title of the question suggests a more flexible approach). That's actually not too hard since we can exploit the symmetry of the ellipse. The key is to provide it with a negative x-radius, since then it will start from the negative x-axis (and proceed clockwise, but we could correct for that by negating the y-radius as well). To do this, we interrupt the call from the node shape to the drawing command and flip the sign of the x-radius. The simplest way to do this is to redefine the \pgfpathellipse macro to do the negation and then call the original macro. The following code does this.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations,shapes,decorations.markings}
\makeatletter
\let\origpgfpathellipse=\pgfpathellipse
\def\revpgfpathellipse#1#2#3{%
  #2%
  \pgf@xa=-\pgf@x
  \origpgfpathellipse{#1}{\pgfqpoint{\pgf@xa}{0pt}}{#3}}
\makeatother

\tikzset{
  reversed ellipse/.style={
    ellipse,
    reverse the ellipse%
  },
  reverse the ellipse/.code={
    \let\pgfpathellipse=\revpgfpathellipse
  }
}
\begin{document}
\begin{tikzpicture}
\node[ellipse,
  draw,
  postaction={
    decorate,
    decoration={
      markings,
      mark=at position 1 with {
        \arrow[line width=5pt,blue]{>}
      }
    }
  }
] at (0,0) {hello world};

\node[reversed ellipse,
  draw,
  postaction={
    decorate,
    decoration={
      markings,
      mark=at position 1 with {
        \arrow[line width=5pt,blue]{>}
      }
    }
  }
] at (0,-2) {hello world};
\end{tikzpicture}

\end{document}

Here's the result:

rotated ellipse

(the arrow got clipped, but you can see where it lies)

[Tex/LaTex] TikZ Layer Invisible

Use \usetikzlibrary and declare and set the layers before you start the tikzpicture environment. When I did this, the missing nodes and edges appeared.

You could move also \tikzstyle, but here it would be better to use \tikzset instead, or to give the styles as option to the tikzpicture environment.

\begin{tikzpicture}[%
  userblock/.style={draw,rectangle,fill=gray!15,minimum height=4em,
    minimum width=4em, node distance=6em},
  tasklabels/.style={node distance=5em]}, 
  compblock/.style={draw=blue, fill=blue!15,node distance=5em,
    minimum height=4em, minimum width=20em, inner sep=1em}]
...

Best Answer

Related Solutions

[Tex/LaTex] Rotate a node but not its content: the case of the ellipse decoration

[Tex/LaTex] TikZ Layer Invisible

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