Drawing a node parallel to any of the x, y or z axis in a rotated tridimensionnal picture

Question

I want to draw a node exactly parallel to one of the three axes that are rotated. One solution could be to compute the axis angle relative to the horizontal line but I don't know what is the best way to do it by myself.

\documentclass[tikz,border=.5cm]{standalone}

\begin{document}
 \begin{tikzpicture}[rotate around y=-80,rotate around x=-100,rotate around z=-20]
       \begin{scope}[->]
      \draw(0,0,0)coordinate(O)--+(1,0,0)node[above]{\(x\)};
      \draw(O)--+(0,1,0)node[above]{\(y\)};
      \draw(O)--+(0,0,1)node[left]{\(z\)};
    \end{scope} 

    \node[draw,rectangle,
     rotate= 20, % 20 is not correct
    ] at(1cm,1cm){ \(\parallel x\) axis};

    \end{tikzpicture}   
\end{document}

You could use the 3d library for that. Just go in a scope canvas is yz plane at x=0. — , Oct 26 '18 at 21:59
Can someone please provide some documentation on how to use 3d library ? — Hafid Boukhoulda, Oct 26 '18 at 22:04

score 3 · Accepted Answer · answered Oct 27 '18 at 00:07

There are two ways of reading your question, so this answer has two parts. The first picture makes use of the 3d library and the second one of calc. Note that, as of now, there is AFAIK no official documentation of the 3d library. On the other hand, the key canvas is xy plane at z=... etc. is sort of self-explaining.

\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{3d}
% small fix for canvas is xy plane at z % https://tex.stackexchange.com/a/48776/121799
\makeatletter
\tikzoption{canvas is xy plane at z}[]{%
    \def\tikz@plane@origin{\pgfpointxyz{0}{0}{#1}}%
    \def\tikz@plane@x{\pgfpointxyz{1}{0}{#1}}%
    \def\tikz@plane@y{\pgfpointxyz{0}{1}{#1}}%
    \tikz@canvas@is@plane}
\makeatother
\usetikzlibrary{calc}
\begin{document}
\begin{tikzpicture}[rotate around y=-80,rotate around x=-100,rotate around z=-20]
    \begin{scope}[->]
      \draw(0,0,0)coordinate(O)--+(1,0,0)node[above]{\(x\)};
      \draw(O)--+(0,1,0)node[above]{\(y\)};
      \draw(O)--+(0,0,1)node[left]{\(z\)};
    \end{scope} 
    \begin{scope}[canvas is xy plane at z=0,transform shape]
    \node[draw,rectangle,] at(1,1){ \(\parallel x\) axis};
    \end{scope}
    \begin{scope}[canvas is yz plane at x=0,transform shape]
    \node[draw,rectangle,] at(1,1){ \(\parallel y\) axis};
    \end{scope}
    \begin{scope}[canvas is zx plane at y=0,transform shape]
    \node[draw,rectangle,] at(1,1){ \(\parallel z\) axis};
    \end{scope}

    \end{tikzpicture}  
%   
    \begin{tikzpicture}[rotate around y=-80,rotate around x=-100,rotate around z=-20]
       \begin{scope}[->]
      \draw(0,0,0)coordinate(O)--+(1,0,0)node[above]{\(x\)};
      \draw(O)--+(0,1,0)node[above]{\(y\)};
      \draw(O)--+(0,0,1)node[left]{\(z\)};
    \end{scope} 
    \path let \p1=(1,0,0),\n1={atan2(\y1,\x1)} in 
    node[draw,rectangle,rotate=\n1+180] at(1cm,1cm){ \(\parallel x\) axis};
    \end{tikzpicture}   
\end{document}

For the record: Jake's patch is now incorporated in v3.1 of TikZ. — Stefan Pinnow, Jan 15 '19 at 19:29
... and now there is also a documentation of the 3d library. — , Jan 15 '19 at 19:33
*g, have fun to add that line to all the other places where I added that line ;) — Stefan Pinnow, Jan 15 '19 at 19:40
@StefanPinnow I don't think it is necessary at any other place. The reason to add it here is this comment. — , Jan 15 '19 at 19:43
Ok, agree. But maybe I add another comment with this information to Jake's answer. Good idea @marmot. — Stefan Pinnow, Jan 15 '19 at 19:52

Drawing a node parallel to any of the x, y or z axis in a rotated tridimensionnal picture

1 Answers1