[Tex/LaTex] Custom shapes in Process Flow Diagram with Tikz

diagramstikz-pgf

I’m trying to draw a process flow diagram using tikz. I'm not an expert, expecially in working with custom nodes.

I saw some other questions about chemical process flow diagrams, but they were general and did not explain how to customize a node to obtain a piece of equipment.

This is what I did so far, using some examples I found:

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}

\begin{document}

\tikzset{HeatEx/.style={draw=black,fill=white,thick,circle,minimum width=1cm}}

\tikzset{Tank/.style={draw=black,fill=white,thick,rectangle,rounded corners=20pt,minimum width=1.5cm,minimum height=3cm,text width=1.5cm,align=center}}

\tikzset{3Phase/.style={draw=black,fill=white,thick,rectangle,rounded corners=20pt,minimum width=4cm,minimum height=1.5cm,text width=4cm,align=center}}

\tikzset{Reactor/.style={draw=black,fill=white,ultra thick,rectangle,rounded corners=20pt,minimum width=1.5cm,minimum height=4cm,text width=1.5cm,align=center}}

\def\COOLER#1#2#3{\node[HeatEx,right=#1 of #2](#3){};
     \draw[thick,-latex] (#3.south east) to[in=-20,out=160] (#3.north west);
}

\def\HEATER#1#2#3#4{\node[HeatEx,below right=#1 and #2 of #3](#4){};
     \draw[thick,-latex] (#4.north east) to[in=20,out=200] (#4.south west);
}

\def\TANK#1#2#3#4{\node[Tank,right=#1 of #2](#3){#4};}

\def\ThreeSEP#1#2#3#4{\node[3Phase,right=#1 of #2](#3){#4};}

\def\REACTOR#1#2#3#4#5{\node[Reactor,below right=#1 and #2 of #3](#4){#5};}

\begin{tikzpicture}
\node (START) {Text};

\TANK{1cm}{START}{F1}{Text}

\node[below right=of F1] (W1) {Text};

\COOLER{1cm}{F1}{C1};

\REACTOR{1cm}{1cm}{C1}{R1}{Text};

\HEATER{1cm}{1cm}{R1}{H1};

\ThreeSEP{1cm}{H1}{S1}{Text};

%Arrows    
\draw[thick,-latex] (START.east) to (F1.west);

\draw[thick,-latex] (F1.south) |- (W1);

\draw[thick,-latex] (F1.east) to (C1.west);

\draw[thick,-latex] (C1.east) -| (R1.north);

\draw[thick,-latex] (R1.south) |- (H1.west);

\draw[thick,-latex] (H1.east) to (S1.west);
\end{tikzpicture}
\end{document}

That produces:
Process flow diagram

I’m not able to get the shapes I want, basically because I don't know how to draw inside a node:

the curved arrow inside the heat exchangers should go a little outside the circle;
the three-phase separator (the horizontal vessel – \ThreeSEP) should be similar to the one in this picture, with the four ports shown:

Three phase separator

I managed to draw the arrow inside the circle thanks to (#3.south east) to (#3.north west), but it would be (may be) simpler if I had “relative reference system” inside each node. Or, at least, something like (#3.south east+3mm,#3.south east+3mm) to (#3.north west+3mm,#3.north west+3mm) (if it even makes sense).

Another issue is the positioning of the nodes, that I control using several inputs and is not so easy to use; it would be easier if I could define the shape and then its relative position (at first I tried only with \tikset{} but I couldn't draw inside the node I defined).
For example, I would like to have the first heat exchanger (\COOLER – C1) above right of the first vessel, but I should define a new style only to change below right to above right, or use the former with negative distances.

Finally, if there is a "smarter" way to do it, I am ready to change my code 🙂 .

Thanks to everyone!

Best Answer

The relative positioning (#3.south east+3mm,#3.south east+3mm) to (#3.north west+3mm,#3.north west+3mm) exists but your syntax is wrong. It should be like this for one coordinate:

($(#3.south east)+(3mm,3mm)$)`

and so on. But I'd use only the horizontal shifting, since the vertical will make the arrow look weird.

Some notes:

Use \newcommand rather than \def, check What is the preferred way of defining a TikZ constant? to see why. Also, the newcommand won't need a ; when you use it.
The \tikzset{} can group all settings without having to recall it each time. Also, if you repeat the same settings for many nodes, you can define a base style, basic in this case, and then use that for all the nodes that need it. So your tikzset won't be too overcrowded. Furthermore, you can override any setting in the basic style if you need (like ultra thick in your case for example). See code.
The extra arrow in the \ThreeSEP command is a new parameter now, the #5 to be precise, which is the coordinate for the top of the arrow. If you can be more precise about the use you will make of it, I can improve it.

Output

Code

\documentclass[margin=10pt]{standalone}
\usepackage{tikz}

\usetikzlibrary{calc, positioning}

\tikzset{
    basic/.style={draw=black,fill=white,thick,rectangle,rounded corners=20pt, align=center},
    HeatEx/.style={draw=black,fill=white,thick,circle,minimum width=1cm},
    Tank/.style={basic, minimum width=1.5cm,minimum height=3cm,text width=1.5cm},
    3Phase/.style={basic, minimum width=4cm,minimum height=1.5cm,text width=4cm},
    Reactor/.style={basic, ultra thick,minimum width=1.5cm,minimum height=4cm,text width=1.5cm},
}

\newcommand{\COOLER}[3]{
    \node[HeatEx,right=#1 of #2](#3){};
    \draw[thick,-latex] ($(#3.south east)+(3mm,0)$) to[out=170,in=-20] ($(#3.north west)+(-3mm,0)$);
}

\newcommand{\HEATER}[4]{
    \node[HeatEx,below right=#1 and #2 of #3](#4){};
    \draw[thick,-latex] ($(#4.north east)+(3mm,0)$) to[out=200,in=20] ($(#4.south west)+(-3mm,0)$);
}

\newcommand{\TANK}[4]{
    \node[Tank,right=#1 of #2](#3){#4};
}

\newcommand{\ThreeSEP}[5]{
    \node[3Phase,right=#1 of #2](#3){#4};
    \draw[thick] (#3.south) to[out=-90,in=-90, looseness=2] node[midway] (sman) {} ($(#3.south)!.5!(#3.south east)$);
    \draw[thick,->] (sman.center) --++ (0,-1cm) -- (#5);
}

\newcommand{\REACTOR}[5]{
    \node[Reactor,below right=#1 and #2 of #3](#4){#5};
}

\begin{document}
\begin{tikzpicture}
    \node (START) {Text};
    \TANK{1cm}{START}{F1}{Text}
    \node[below right=of F1] (W1) {Text};
    \COOLER{1cm}{F1}{C1}
    \REACTOR{1cm}{1cm}{C1}{R1}{Text}
    \HEATER{1cm}{1cm}{R1}{H1}
    \ThreeSEP{1cm}{H1}{S1}{Hello}{15,-12}

%Arrows    
    \draw[thick,-latex] (START.east) to (F1.west);
    \draw[thick,-latex] (F1.south) |- (W1);
    \draw[thick,-latex] (F1.east) to (C1.west);
    \draw[thick,-latex] (C1.east) -| (R1.north);
    \draw[thick,-latex] (R1.south) |- (H1.west);
    \draw[thick,-latex] (H1.east) to (S1.west);
\end{tikzpicture}
\end{document}

Shape declaration:

\pgfdeclareshape{oplus}
%
% Shaped like '\oplus' math symbol. Based on 'circle' shape
%
{%
  % All anchors are taken from the 'circle' shape:
  \inheritsavedanchors[from={circle}]%
  \inheritanchor[from={circle}]{center}%
  \inheritanchor[from={circle}]{mid}%
  \inheritanchor[from={circle}]{base}%
  \inheritanchor[from={circle}]{north}%
  \inheritanchor[from={circle}]{south}%
  \inheritanchor[from={circle}]{west}%
  \inheritanchor[from={circle}]{east}%
  \inheritanchor[from={circle}]{mid west}%
  \inheritanchor[from={circle}]{mid east}%
  \inheritanchor[from={circle}]{base west}%
  \inheritanchor[from={circle}]{base east}%
  \inheritanchor[from={circle}]{north west}%
  \inheritanchor[from={circle}]{south west}%
  \inheritanchor[from={circle}]{north east}%
  \inheritanchor[from={circle}]{south east}%
  \inheritanchorborder[from={circle}]%
  %
  % Only the background path is different
  %
  \backgroundpath{%
    % First the existing 'circle' code:
    \pgfutil@tempdima=\radius%
    \pgfmathsetlength{\pgf@xb}{\pgfkeysvalueof{/pgf/outer xsep}}%
    \pgfmathsetlength{\pgf@yb}{\pgfkeysvalueof{/pgf/outer ysep}}%
    \ifdim\pgf@xb<\pgf@yb%
      \advance\pgfutil@tempdima by-\pgf@yb%
    \else%
      \advance\pgfutil@tempdima by-\pgf@xb%
    \fi%
    \pgfpathcircle{\centerpoint}{\pgfutil@tempdima}%
    %
    % Now the | and -- lines:
    \pgfmoveto{\pgfpointadd{\centerpoint}{\pgfpoint{0pt}{\pgfutil@tempdima}}}%
    \pgflineto{\pgfpointadd{\centerpoint}{\pgfpoint{0pt}{-\pgfutil@tempdima}}}%
    \pgfmoveto{\pgfpointadd{\centerpoint}{\pgfpoint{\pgfutil@tempdima}{0pt}}}%
    \pgflineto{\pgfpointadd{\centerpoint}{\pgfpoint{-\pgfutil@tempdima}{0pt}}}%
  }%
}

Usage example:

\documentclass{standalone}

\usepackage{tikz}
\usepackage{pgfshape_oplus}

\begin{document}
\begin{tikzpicture}
  \node [draw=blue,shape=oplus] {Test};
\end{tikzpicture}
\end{document}

Result:

Result

You might also want to draw the additional lines in the \foregroundpath instead. For this see the forbidden sign shape in the file pgflibraryshapes.symbols.code.tex is an good example.

[Tex/LaTex] Tikz : node filling with text

The vertical filling you can do when you measure height with the help of \pgfgetlastxy:

Code

\documentclass[parskip]{scrartcl}
\usepackage[margin=15mm]{geometry}
\usepackage{tikz}
\usetikzlibrary{positioning}
\usepackage[scaled]{helvet}
\renewcommand*\familydefault{\sfdefault} %% Only if the base font of the document is to be sans serif
\usepackage[T1]{fontenc}

\newcommand{\computeheight}[2]% name of node, name of targetmacro
{ \path (#1.south west);
  \pgfgetlastxy{\xsw}{\ysw}
  \path (#1.north east);
  \pgfgetlastxy{\xne}{\yne}
  %\pgfmathsetlengthmacro{\nodewidth}{\xne-\xsw}% not needed here
  \pgfmathsetlengthmacro{\nodeheight}{\yne-\ysw}
  %\xdef\widthofnode{\nodewidth}
  \expandafter\xdef\csname #2\endcsname{\nodeheight}
}

\begin{document}

\begin{tikzpicture} [remember picture,overlay]
  \node[right](name)[align = left, inner sep = 2pt] {\fontsize{42pt}{0pt}\selectfont{My Name} \\
  \fontsize{20}{5pt}\selectfont{My function}};

    % get height of node "name"
  \computeheight{name}{nameheight}

  \draw (name.north west) -- +(18cm, 0);
  \draw (name.south west) -- +(18cm, 0);

    % helper coordinate
    \coordinate[right=5.0cm of name.north east, anchor=north west] (about);
    % the data you want to use; the {} is for protecting commas in the entries,
    % so it's not neccessary here
    \foreach \t [count=\c] in {{mymail@mail.com},{+45 555 555},{my adress},{zipcode City}}
    {   \pgfmathsetlengthmacro{\topdistance}{(\c-1)*\nameheight/4+\nameheight/4*0.5}
        \node[below=\topdistance of about,align=left,anchor=west] (about\c) {\fontsize{12pt}{12pt}\selectfont{\t}};
    }
\end{tikzpicture}

\end{document}

Output

enter image description here

Best Answer

Output

Code

Related Solutions

[Tex/LaTex] How to draw inside a TikZ node, using node style

Shape declaration:

Usage example:

Result:

[Tex/LaTex] Tikz : node filling with text

Code

Output

Related Question