% !TeX TXS-program:compile = txs:///pdflatex

\documentclass[margin=5mm]{standalone}
\usepackage{esvect}
\usepackage{tikz}
\newcommand\vect[1]{\vv{#1}}

\begin{document}

\begin{tikzpicture}[x=0.85cm,y=0.85cm,line width=1pt,line join=bevel,>=latex]
	%arêtes
	\draw (0,1.7)--(6.5,0)--(6.5,7.2)--(0,8.9)--cycle ; %BCGF
	\draw (6.5,0)--(10,2.6)--(10,9.8)--(6.5,7.2)--cycle ; %CDHG
	\draw (10,9.8)--(3.5,11.5)--(0,8.9) ; %HEF
	\draw[dashed] (0,1.7)--(3.5,4.3)--(3.5,11.5) ; %BAE
	\draw[dashed] (3.5,4.3)--(10,2.6) ; %AD
	\draw[dashed] (3.5,4.3)--(6.5,7.2) ; %AG
	\draw[dashed] (3.5,11.5)--(6.5,0) ; %EC
	%vecteurs
	\draw[->,line width=1.25pt] (3.5,4.3)--(3.0625,3.975) ;
	\draw[->,line width=1.25pt] (3.5,4.3)--(4.3125,4.0875) ;
	\draw[->,line width=1.25pt] (3.5,4.3)--(3.5,5.2) ;
	%labels simples
	\foreach \Point/\Nom/\Pos in {(0,1.7)/B/below,(6.5,0)/C/below,(6.5,7.2)/G/above,(0,8.9)/F/above,(10,2.6)/D/right,(10,9.8)/H/above,(3.5,11.5)/E/above,(3.5,4.3)/A/below}
	\draw \Point node[\Pos] {\Nom} ;
	%labels "dot"
	\foreach \Point/\Nom/\Pos in {(5,5.73)/$\Omega$/right,(0.88,2.35)/P/above,(3.5,9.7)/Q/left,(1.625,8.475)/R/above}
	\filldraw \Point circle[radius=2pt] node[\Pos] {\Nom} ;
	%labels vecteurs
	\foreach \Vecteur/\Nom/\Pos in {(3.0625,3.975)/$\vect{\imath}$/above,(4.3125,4.0875)/$\vect{\jmath}$/above,(3.5,5.2)/$\vect{k}$/left}{\draw \Vecteur node[\Pos] {\Nom} ;}
\end{tikzpicture}

\end{document}