Btukfyl

I came across the following to draw a rope connecting two points. Is this a custom-made object, or is this something that came from a package?

If it is custom-made, what is the best way of constructing something like this without the code being overly convoluted?

It is not too difficult to draw something along these lines.

documentclass[tikz,border=3.14mm]{standalone}

usetikzlibrary{decorations.markings}

begin{document}

  begin{tikzpicture}

    draw[decorate,decoration={markings,

    mark=between positions 2mm and pgfdecoratedpathlength-2mm step 2mm

      with

      {

        draw[ultra thick,gray] 

        (-3.5mm,-1.25mm) to[out=0,in=160] (-2mm,-1.25mm) to[out=-20,in=160] 

        (2mm,1.25mm) to[out=-20,in=180] (3.5mm,1.25mm);

      }}] 

    (0,0) -- (4,-4);

    fill (0,0) circle (3mm);   

  end{tikzpicture}

end{document}

An arguably cleaner way is to do it with decorations.

documentclass[tikz,border=3.14mm]{standalone}

usetikzlibrary{decorations} %  decorations.text just 4 fun



pgfkeys{/tikz/.cd,

    rope width/.store in=RopeWidth,

    rope width=5pt,

    rope step/.store in=RopeStep,

    rope step=2mm,

}



pgfdeclaredecoration{rope}{initial}

{% 

state{initial}[width=RopeStep,next state=cont] {

    pgfmoveto{pgfpoint{0pt}{-RopeWidth/2}}

    pgfpathcurveto

    {pgfpoint{5*RopeStep/6}{0.25*RopeWidth}}

    {pgfpoint{7*RopeStep/6}{0.45*RopeWidth}}

    {pgfpoint{1.5*RopeStep}{RopeWidth/2}}

     pgfpathcurveto

    {pgfpoint{10*RopeStep/6}{0.55*RopeWidth}}

    {pgfpoint{11*RopeStep/6}{0.6*RopeWidth}}

    {pgfpoint{13.5*RopeStep/6}{RopeWidth/2}}

    pgfcoordinate{lastup}{pgfpoint{-1.5*RopeStep/6}{-RopeWidth/2}}

  }

  state{cont}[width=RopeStep]{ 

     pgfmoveto{pgfpointanchor{lastup}{center}}

     pgfpathcurveto

    {pgfpoint{-5*RopeStep/6}{-0.6*RopeWidth}}

    {pgfpoint{-4*RopeStep/6}{-0.55*RopeWidth}}

    {pgfpoint{-3*RopeStep/6}{-0.55*RopeWidth}}

     pgfpathcurveto

    {pgfpoint{-RopeStep/6}{-0.45*RopeWidth}}

    {pgfpoint{RopeStep/6}{-0.25*RopeWidth}}

    {pgfpoint{3*RopeStep/6}{0pt}}

    pgfpathcurveto

    {pgfpoint{5*RopeStep/6}{0.25*RopeWidth}}

    {pgfpoint{7*RopeStep/6}{0.45*RopeWidth}}

    {pgfpoint{9*RopeStep/6}{RopeWidth/2}}

     pgfpathcurveto

    {pgfpoint{10*RopeStep/6}{0.55*RopeWidth}}

    {pgfpoint{11*RopeStep/6}{0.6*RopeWidth}}

    {pgfpoint{13.5*RopeStep/6}{RopeWidth/2}}

    pgfcoordinate{lastup}{pgfpoint{-1.5*RopeStep/6}{-RopeWidth/2}}

  }

  state{final}[width=5pt]

  {

     pgfmoveto{pgfpointanchor{lastup}{center}}

     pgfpathcurveto

    {pgfpoint{-5*RopeStep/6}{-0.6*RopeWidth}}

    {pgfpoint{-4*RopeStep/6}{-0.55*RopeWidth}}

    {pgfpoint{-0.5*RopeStep}{-0.55*RopeWidth}}

     pgfpathcurveto

    {pgfpoint{-RopeStep/6}{-0.45*RopeWidth}}

    {pgfpoint{RopeStep/6}{-0.25*RopeWidth}}

    {pgfpoint{0.5*RopeStep}{0pt}}

    pgfmoveto{pgfpointdecoratedpathlast}

  }

}

begin{document}

begin{tikzpicture}[decoration=rope]

  draw[red,thick,decorate,rope width=8pt] (-4,0) to[out=0,in=90] (0,-4);

  draw[gray,thick,decorate] (0,0) to (4,-4);

  draw[blue,ultra thick,decorate,rope width=8pt] (4,0) to (8,-4);

  fill (-4,0) circle (8pt) (0,0) circle (8pt) (4,0) circle (8pt);

end{tikzpicture}  

end{document}

All these decorations leave some room for improvement, in particular the one along the curved path has small gaps.

ADDENDUM: Here is a version that does not leave gaps. Yet it does not look too good when the curvature is large.

documentclass[tikz,border=3.14mm]{standalone}

usetikzlibrary{decorations} %  decorations.text just 4 fun

newcounter{ropept}

pgfkeys{/tikz/.cd,

    rope width/.store in=RopeWidth,

    rope width=5pt,

    rope step/.store in=RopeStep,

    rope step=2mm,

}



pgfdeclaredecoration{rope}{initial}

{% 

state{initial}[width=RopeStep,next state=cont] {

    pgfmoveto{pgfpoint{0pt}{-RopeWidth/2}}

    pgfpathcurveto

    {pgfpoint{5*RopeStep/6}{0.25*RopeWidth}}

    {pgfpoint{7*RopeStep/6}{0.45*RopeWidth}}

    {pgfpoint{1.5*RopeStep}{RopeWidth/2}}

     pgfpathcurveto

    {pgfpoint{10*RopeStep/6}{0.55*RopeWidth}}

    {pgfpoint{11*RopeStep/6}{0.6*RopeWidth}}

    {pgfpoint{13.5*RopeStep/6}{RopeWidth/2}}

    setcounter{ropept}{0}

    pgfcoordinate{lastup-theropept}{pgfpoint{-1.5*RopeStep/6}{-RopeWidth/2}}

    pgfcoordinate{rope-auxA-theropept}{pgfpoint{13.5*RopeStep/6}{RopeWidth/2}}

  }

  state{cont}[width=RopeStep]{ 

     pgfmoveto{pgfpointanchor{lastup-theropept}{center}}

     pgfpathcurveto

    {pgfpoint{-5*RopeStep/6}{-0.6*RopeWidth}}

    {pgfpoint{-4*RopeStep/6}{-0.55*RopeWidth}}

    {pgfpoint{-3*RopeStep/6}{-0.55*RopeWidth}}

     pgfpathcurveto

    {pgfpoint{-RopeStep/6}{-0.45*RopeWidth}}

    {pgfpoint{RopeStep/6}{-0.25*RopeWidth}}

    {pgfpoint{3*RopeStep/6}{0pt}}

    pgfpathcurveto

    {pgfpoint{5*RopeStep/6}{0.25*RopeWidth}}

    {pgfpoint{7*RopeStep/6}{0.45*RopeWidth}}

    {pgfpoint{9*RopeStep/6}{RopeWidth/2}}

     pgfpathcurveto

    {pgfpoint{10*RopeStep/6}{0.55*RopeWidth}}

    {pgfpoint{11*RopeStep/6}{0.6*RopeWidth}}

    {pgfpoint{13.5*RopeStep/6}{RopeWidth/2}}

    pgfmoveto{pgfpointanchor{rope-auxA-theropept}{center}}

    pgfpathlineto{pgfpoint{9*RopeStep/6}{RopeWidth/2}}

    stepcounter{ropept}

    pgfcoordinate{lastup-theropept}{pgfpoint{-1.5*RopeStep/6}{-RopeWidth/2}}

    pgfcoordinate{rope-auxA-theropept}{pgfpoint{13.5*RopeStep/6}{RopeWidth/2}}

  }

  state{final}[width=5pt]

  {

     pgfmoveto{pgfpointanchor{lastup-theropept}{center}}

     pgfpathcurveto

    {pgfpoint{-5*RopeStep/6}{-0.6*RopeWidth}}

    {pgfpoint{-4*RopeStep/6}{-0.55*RopeWidth}}

    {pgfpoint{-0.5*RopeStep}{-0.55*RopeWidth}}

     pgfpathcurveto

    {pgfpoint{-RopeStep/6}{-0.45*RopeWidth}}

    {pgfpoint{RopeStep/6}{-0.25*RopeWidth}}

    {pgfpoint{0.5*RopeStep}{0pt}}

    pgfmoveto{pgfpointdecoratedpathlast}

    xdefLastRope{theropept}

  }

}

begin{document}

begin{tikzpicture}[decoration=rope]

  draw[decorate] plot[smooth cycle, fill=yellow, thick] coordinates{ (4.,8.4) (6.5,9.) (8.,9) (9.,8.1) (11.34,6.18) (11,4) (11.3,2.2) (10.2 7,0.7 ) (8. 4,0.14) (6.2,0.29) (4.40,0.51) (3.2,0.29) (1.5,0.34) } ; 

  typeout{theropept}

end{tikzpicture}  

end{document}