[Tex/LaTex] 2D and 3D vectors in Tikz

graphicsgraphstikz-3dplottikz-pgfvector

I would like to draw some 2D and 3D vectors in Tikz with certain properties. The following primitive graph sums what I desire:

g

  • I just need the first quadrant of the Cartesian coordinate system for my representation.

  • I need the vector to be connected to the respective values on the distinct dimensions(not a projection, just orthogonal dashed lines).

The code segment below does what I want to achieve in 3D with two exceptions:

  • The projections on the xy plane and z dimension are given instead of connecting the head of the vector to the corresponding value in each dimension.

  • Numerical values are missing in dimensions.

Code:

\documentclass[tikz]{standalone}
\usepackage{tikz-3dplot}
\begin{document}

\tdplotsetmaincoords{60}{120}
\begin{tikzpicture}
    [scale=3,
    tdplot_main_coords,
    axis/.style={->,blue,thick},
    vector/.style={-stealth,red,very thick},
    vector guide/.style={dashed,red,thick}]

%standard tikz coordinate definition using x, y, z coords
\coordinate (O) at (0,0,0);

%tikz-3dplot coordinate definition using r, theta, phi coords
\tdplotsetcoord{P}{.8}{55}{60}

%draw axes
\draw[axis] (0,0,0) -- (1,0,0) node[anchor=north east]{$x$};
    \draw[axis] (0,0,0) -- (0,1,0) node[anchor=north west]{$y$};
    \draw[axis] (0,0,0) -- (0,0,1) node[anchor=south]{$z$};

%draw a vector from O to P
\draw[vector] (O) -- (P);

%draw guide lines to components
\draw[vector guide] (O) -- (Pxy);
\draw[vector guide] (Pxy) -- (P);
\end{tikzpicture}
\end{document}

Best Answer

This alternative provides Cartesian coordinates, serving as a complement to Perter Grill's solution.

enter image description here

Code

\documentclass[tikz,border=1cm]{standalone} 
\usepackage{tikz-3dplot} 
\begin{document}

\tdplotsetmaincoords{60}{120} 
\begin{tikzpicture} [scale=3, tdplot_main_coords, axis/.style={->,blue,thick}, 
vector/.style={-stealth,red,very thick}, 
vector guide/.style={dashed,red,thick}]

%standard tikz coordinate definition using x, y, z coords
\coordinate (O) at (0,0,0);

%tikz-3dplot coordinate definition using x, y, z coords

\pgfmathsetmacro{\ax}{0.8}
\pgfmathsetmacro{\ay}{0.8}
\pgfmathsetmacro{\az}{0.8}

\coordinate (P) at (\ax,\ay,\az);

%draw axes
\draw[axis] (0,0,0) -- (1,0,0) node[anchor=north east]{$x$};
\draw[axis] (0,0,0) -- (0,1,0) node[anchor=north west]{$y$};
\draw[axis] (0,0,0) -- (0,0,1) node[anchor=south]{$z$};

%draw a vector from O to P
\draw[vector] (O) -- (P);

%draw guide lines to components
\draw[vector guide]         (O) -- (\ax,\ay,0);
\draw[vector guide] (\ax,\ay,0) -- (P);
\draw[vector guide]         (P) -- (0,0,\az);
\draw[vector guide] (\ax,\ay,0) -- (0,\ay,0);
\draw[vector guide] (\ax,\ay,0) -- (0,\ay,0);
\draw[vector guide] (\ax,\ay,0) -- (\ax,0,0);
\node[tdplot_main_coords,anchor=east]
at (\ax,0,0){(\ax, 0, 0)};
\node[tdplot_main_coords,anchor=west]
at (0,\ay,0){(0, \ay, 0)};
\node[tdplot_main_coords,anchor=south]
at (0,0,\az){(0, 0, \az)};
\end{tikzpicture}
\end{document}
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