4

All I want to do is to rotate the axes of the accepted answer of the question in

How to draw and annotate a spherical coordinate system

such that the new z-axis stays where the current y-axis is.

My new axes (say, x', y' and z') should seem to be exactly where those xyz-axes are but with the following correspondences:

  • z' <-- y
  • y' <-- x
  • x' <-- z

I don't want simply to change the axes' labels, because I want to work with the axis z' still being along the direction (0,0,1) and the angle theta must still come from it.

Stuff from How to draw and annotate a spherical coordinate system below:

enter image description here

\documentclass{article} 

\usepackage{tikz}
\usepackage{tikz-3dplot}

\begin{document}
\tdplotsetmaincoords{60}{110}
%
\pgfmathsetmacro{\rvec}{.8}
\pgfmathsetmacro{\thetavec}{30}
\pgfmathsetmacro{\phivec}{60}
%
\begin{tikzpicture}[scale=5,tdplot_main_coords]
\coordinate (O) at (0,0,0);
\draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]{$x$};
\draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]{$y$};
\draw[thick,->] (0,0,0) -- (0,0,1) node[anchor=south]{$z$};
\tdplotsetcoord{P}{\rvec}{\thetavec}{\phivec}
\draw[-stealth,color=red] (O) -- (P) node[above right] {$P$};
\draw[dashed, color=red] (O) -- (Pxy);
\draw[dashed, color=red] (P) -- (Pxy);
\tdplotdrawarc{(O)}{0.2}{0}{\phivec}{anchor=north}{$\phi$}
\tdplotsetthetaplanecoords{\phivec}
\tdplotdrawarc[tdplot_rotated_coords]{(0,0,0)}{0.5}{0}%
    {\thetavec}{anchor=south west}{$\theta$}
\end{tikzpicture}
\end{document}

I couldn't to that with \tdplotsetmaincoords{}{} because that command only rotates around x-axis and then around the new z-axis (from the configuration showed below), and reaching my configuration requires a third rotation (like Euler angles) or rotation around y-axis.

This is a picture from Changing axes in tikz-3dplot picture (bobobobo's answer) showing the start configuration for rotations with tdplotsetmaincoords

Start configuration for rotations with command tdplotsetmaincoords{}{}.

Community
  • 1
Leonardo Castro
  • 1,280

1 Answers1

3

I was finally able to do that with \tdplotsetrotatedcoords{-90}{-90}{0}. I also had to put \tdplotsetrotatedthetaplanecoords{\phivec} instead of \tdplotsetthetaplanecoords{\phivec}.

Rotated spherical coordinate angles.

\documentclass{article} 

\usepackage{tikz}
\usepackage{tikz-3dplot}

\begin{document}

\tdplotsetmaincoords{60}{110}
\tdplotsetrotatedcoords{-90}{-90}{0}
%
\begin{tikzpicture}[scale=5,tdplot_rotated_coords]
  \coordinate (O) at (0,0,0);
  \draw[thick,->] (0,0,0) -- (1,0,0) node[anchor=north east]{$x$};
  \draw[thick,->] (0,0,0) -- (0,1,0) node[anchor=north west]{$y$};
  \draw[thick,->] (0,0,0) -- (0,0,1) node[anchor=south]{$z$};
  \def\rvec{1}
  \def\thetavec{45}
  \def\phivec{30}
  \tdplotsetcoord{P}{\rvec}{\thetavec}{\phivec}
  \draw[-stealth,color=red] (O) -- (P) node[above right] {$P$};
  \draw[dashed, color=red] (O) -- (Pxy);
  \draw[dashed, color=red] (P) -- (Pxy);
%  \draw[dashed, color=red] (P) -- (Pyz);
%  \draw[dashed, color=red] (O) -- (Pxz);
%  \draw[dashed, color=red] (P) -- (Pxz);
  \tdplotdrawarc[tdplot_rotated_coords]{(O)}{0.2}{0}{\phivec}{anchor=north east}{$\phi$}
  \tdplotsetrotatedthetaplanecoords{\phivec}
  \tdplotdrawarc[tdplot_rotated_coords]{(0,0,0)}{0.5}{0}{\thetavec}{anchor=south west}{$\theta$}
\end{tikzpicture}

\end{document}
Leonardo Castro
  • 1,280