Drawing an arrow with 2 breaks of 90 degree using Tikz

Question

Im trying to make a tikzpicture that describes a process as following:

Is there a way to create a line with 2 breaks like added in thicker?

% Definition of blocks:
\tikzset{block/.style    = {draw, thick, rectangle, minimum height = 3em,minimum width = 3em,node distance = 2.4cm},
  sum/.style      = {draw, circle, node distance = 1.5cm}, % Adder
  input/.style    = {coordinate}, % Input
  output/.style   = {coordinate} % Output
    ncbar angle/.initial=90,
    ncbar/.style={
        to path=(\tikztostart)
        -- ($(\tikztostart)!#1!\pgfkeysvalueof{/tikz/ncbar angle}:(\tikztotarget)$)
        -- ($(\tikztotarget)!($(\tikztostart)!#1!\pgfkeysvalueof{/tikz/ncbar angle}:(\tikztotarget)$)!\pgfkeysvalueof{/tikz/ncbar angle}:(\tikztostart)$)
        -- (\tikztotarget)
    },
    ncbar/.default=0.5cm,
  }

% Defining string as labels of certain blocks.
\newcommand{\suma}{\Large}
\newcommand{\inte}{$\displaystyle \int$}
\newcommand{\derv}{\Large $\frac{d}{dt}$}

\begin{tikzpicture}[auto, thick, node distance=2cm, >=triangle 45]
    \draw
    %% Drawing the blocks of first filter :
    node [input, name=input1] {} 
    node [sum, right of=input1] (sum1) {\suma}
    node [block, right of=sum1] (inte1) {\inte}
    node [block, right of=inte1] (inte2) {\inte}
    node [block, right of=inte2] (gain1) {\Large $\frac{1}{V_{c}(t_{f}-t)}$}
    node [block, right of=gain1] (gain2) {\derv}
    node [block, right of=gain2] (gain3) {$N'V_{c}$}
    node [sum, right of=gain3] (sum2) {\suma}
    node [block, above of=gain1] (gain4) {$0.5N'$};

    % Joining blocks. 
    % Commands \draw with options like [->] must be written individually
    \draw[->](input1) -- node {$a_{T}$}(sum1);
    \draw[->](sum1) -- node {$\ddot{y}$} (inte1);
    \draw[->](inte1) -- node {$\dot{y}$} (inte2);
    \draw[->](inte2) -- node {$y$} (gain1);
    \draw[->](gain1) -- node {$\lambda$} (gain2);
    \draw[->](gain2) -- node {$\dot{\lambda}$} (gain3);
    \draw[->](sum1) -- node {$\ddot{y}$} (inte1);
    \draw[->](gain3) -- node {} (sum2);
    \draw[->](sum1) |- node {} (gain4);
    \draw[->](gain4) -| node {} (sum2);
    \draw  (sum2) to [ncbar] (sum1);
\end{tikzpicture}

However im getting an error when using [ncbar]

Thank you.

However the arrow always goes to the same direction in this example, i want it to do like a 180 degree return — Ben, Jun 02 '17 at 20:54
Oh, right, so you're after https://tex.stackexchange.com/questions/55068/is-there-a-tikz-equivalent-to-the-pstricks-ncbar-command — Torbjørn T., Jun 02 '17 at 20:58
You could also do something like \draw [->] (ret1) -- ++(1cm,0) |- (sum1); — Torbjørn T., Jun 02 '17 at 21:03
Somewhy the code there isnt working, used all packages needed and gets and error. — Ben, Jun 02 '17 at 21:13
Impossible to say why that may be, when you neither tell us exactly what you tried, nor said what the error message is. If you edit your question with a complete example, we can probably tell you what went wrong. — Torbjørn T., Jun 02 '17 at 21:17
You've forgotten a comma after the definition of the output style. — Torbjørn T., Jun 02 '17 at 21:27
And ncbar style has a parameter, put ncbar={.1}, for example. — CarLaTeX, Jun 02 '17 at 21:33
ye did this even an arrow -> worked, however cant add text below/above/near end of it. — Ben, Jun 02 '17 at 21:37

score 3 · Accepted Answer · answered Jun 02 '17 at 21:56

As mentioned in a comment, Is there a TikZ equivalent to the PSTricks \ncbar command? describes a couple of ways of making such a line. As you noted, it seems adding nodes along a path like that doesn't seem to work.

A different method of achieving the same is to make the path in two steps, and go via a coordinate relative to the first node, e.g.

\draw  (sum2) -- node {1} ++(0,-2cm) -| (sum1) node[pos=0.25] {2} node[pos=0.75] {3};

This lets you use node with pos as usual.

\documentclass[landscape]{article}
\usepackage{tikz}
\usetikzlibrary{calc,arrows}
% Definition of blocks:
\tikzset{block/.style    = {draw, thick, rectangle, minimum height = 3em,minimum width = 3em,node distance = 2.4cm},
  sum/.style      = {draw, circle, node distance = 1.5cm}, % Adder
  input/.style    = {coordinate}, % Input
  output/.style   = {coordinate}, % Output
}

% Defining string as labels of certain blocks.
\newcommand{\suma}{\Large}
\newcommand{\inte}{$\displaystyle \int$}
\newcommand{\derv}{\Large $\frac{d}{dt}$}
\begin{document}


\begin{tikzpicture}[auto, thick, node distance=2cm, >=triangle 45]
    \draw
    %% Drawing the blocks of first filter :
    node [input, name=input1] {} 
    node [sum, right of=input1] (sum1) {\suma}
    node [block, right of=sum1] (inte1) {\inte}
    node [block, right of=inte1] (inte2) {\inte}
    node [block, right of=inte2] (gain1) {\Large $\frac{1}{V_{c}(t_{f}-t)}$}
    node [block, right of=gain1] (gain2) {\derv}
    node [block, right of=gain2] (gain3) {$N'V_{c}$}
    node [sum, right of=gain3] (sum2) {\suma}
    node [block, above of=gain1] (gain4) {$0.5N'$};

    % Joining blocks. 
    % Commands \draw with options like [->] must be written individually
    \draw[->](input1) -- node {$a_{T}$}(sum1);
    \draw[->](sum1) -- node {$\ddot{y}$} (inte1);
    \draw[->](inte1) -- node {$\dot{y}$} (inte2);
    \draw[->](inte2) -- node {$y$} (gain1);
    \draw[->](gain1) -- node {$\lambda$} (gain2);
    \draw[->](gain2) -- node {$\dot{\lambda}$} (gain3);
    \draw[->](sum1) -- node {$\ddot{y}$} (inte1);
    \draw[->](gain3) -- node {} (sum2);
    \draw[->](sum1) |- node {} (gain4);
    \draw[->](gain4) -| node {} (sum2);

    \draw  (sum2) -- node {1} ++(0,-2cm) -| (sum1) node[pos=0.25] {2} node[pos=0.75] {3};
\end{tikzpicture}
\end{document}

Drawing an arrow with 2 breaks of 90 degree using Tikz

1 Answers1