{{ latex:projection.png ? 300 }} Example of adding and projecting vectors. For more, please visit https://tikz.net/category/physics/particle-physics/. % Author: Izaak Neutelings (June 2017) \documentclass{article} \usepackage{amsmath} \usepackage{tikz} \tikzset{>=latex} % for LaTeX arrow head \usetikzlibrary{calc} % to sum coordinates \newcommand*{\vv}[1]{\vec{\mkern0mu#1}} % correct \vec misalignment % split figures into pages \usepackage[active,tightpage]{preview} \PreviewEnvironment{tikzpicture} \setlength\PreviewBorder{5pt} \begin{document} % PZETA VIS \begin{tikzpicture} % vector labels \def\pT{ \vv{p}^\text{\tiny\,vis}_\text{\tiny\,T}} \def\pTA{\vv{p}^\text{\tiny\,vis}_\text{\tiny\,T,1}} \def\pTB{\vv{p}^\text{\tiny\,vis}_\text{\tiny\,T,2}} % define point \coordinate (O) at (0.0, 0.0); \coordinate (Z) at (3.5, 0.0); \coordinate (A) at (1.0, 1.8); \coordinate (B) at (1.2,-2.16); \coordinate (AB) at ($(A)+(B)$); \path let \p{AB}=(AB) in coordinate (P) at (\x{AB},0); % projection % axis \draw[->,thick,dashed] (-0.8,0) -- (Z) node[at end,below] {$\vv{\zeta}$}; % main vectors \draw[->,thick,color=red] (O) -- (A) node[below=4pt,left=4pt,color=red] {$\pTA$}; \draw[->,thick,color=red] (O) -- (B) node[above=2pt,left=2pt,color=red] {$\pTB$}; \draw[->,color=red] (O) -- (AB) node[below=4pt,right,color=red,scale=1] {$\pT$}; %{$\sq\pTA+\,\pTB$}; % helplines \draw[dashed,color=red] (A) -- (AB); \draw[dashed,color=red] (B) -- (AB); \draw[dashed,color=purple] (AB) -- (P); % vector sum \draw[->,thick,color=purple] (O) -- (P) node[right=4pt,above,color=purple] {$\vv{p}^\text{\tiny\,vis}_{\tiny\,\zeta}$}; \end{tikzpicture} \end{document}