\documentclass{article}
%% compiler avec lualatex
\usepackage[margin=2.5cm]{geometry}
\usepackage{luamesh}
\usepackage{fontspec}
\usepackage{multido}
\pagestyle{empty}
\begin{document}

\buildMesh[print=points,  meshpoint = I, color=red]{(0,0);(3.5,3);(7,0);(7.5,5);(1.61,3.14);(3,1);(6,1.5)}

\buildMesh[tikz, bbox = show]{(0,0);(3.5,3);(7,0);(7.5,5);(1.61,3.14);(3,1);(6,1.5)}

\buildMesh[mode=ext]{mesh.txt}

\meshAddOnePoint[
meshpoint = x,
colorNew =green!20!red,
colorBack=red!10,
colorCircle = green!70,
scale=0.6cm]
{(0,0);(3.5,3);(7,0);(7.5,5);(1.61,3.14);(6,4)}{(3,1)}
\meshAddOnePoint[
meshpoint = x,
colorBack=red!10,
colorNew = green!20!red,
scale=0.6cm,
step=cavity]
{(0,0);(3.5,3);(7,0);(7.5,5);(1.61,3.14);(6,4)}{(3,1)}
\meshAddOnePoint[
meshpoint = x,
colorBack=red!10,
colorNew = green!20!red,
scale=0.6cm,
step=newtriangles,
newpoint = y
]
{(0,0);(3.5,3);(7,0);(7.5,5);(1.61,3.14);(6,4)}{(3,1)}





\end{document}
