\documentclass[tikz,border=6pt]{standalone} \usepackage{tikz-3dplot} \usepackage{amsmath,amssymb} \usetikzlibrary{arrows.meta,calc} \begin{document} \tdplotsetmaincoords{58}{-14} \begin{tikzpicture}[tdplot_main_coords,scale=1.45,line join=round,line cap=round, >={Stealth[length=2.6mm,width=1.8mm]}] % a piece of R: a prism over the pentagon F (its top face, z = h) \def\h{1.5} \coordinate (A) at (0,0,\h); \coordinate (B) at (4.2,0,\h); \coordinate (C) at (4.6,2.6,\h); \coordinate (D) at (2.2,3.8,\h); \coordinate (E) at (-0.4,2.4,\h); \coordinate (A0) at (0,0,0); \coordinate (B0) at (4.2,0,0); \coordinate (C0) at (4.6,2.6,0); \coordinate (D0) at (2.2,3.8,0); \coordinate (E0) at (-0.4,2.4,0); % hidden edges \draw[gray!55,dashed] (B0)--(C0)--(D0)--(E0)--(A0) (C0)--(C) (D0)--(D) (E0)--(E); % the visible side face \fill[blue!8] (A)--(B)--(B0)--(A0)--cycle; \draw[gray!75] (A)--(A0)--(B0)--(B); % the face F \fill[orange!8] (A)--(B)--(C)--(D)--(E)--cycle; \draw[black!80,thick] (A)--(B)--(C)--(D)--(E)--cycle; % F cap {sigma > 0} \fill[teal!22,draw=teal!70!black,thick] plot[smooth cycle,domain=0:350,samples=36,variable=\t] ({2.2+1.3*cos(\t)},{1.7+0.75*sin(\t)},\h); % J on the boundary (angle 225), chord along the tangent \coordinate (J) at (1.2808,1.1697,\h); \coordinate (J1) at (3.3044,0,\h); \coordinate (J2) at (-0.3520,2.1120,\h); \draw[red!70!black,very thick] (J2)--(J1); \draw[->,red!70!black,very thick] (J)--($(J)!0.7!(J1)$); % along the edge AB from J1 to the vertex B \draw[->,blue!60!black,very thick] (J1)--($(J1)!0.72!(B)$); \fill[black] (J) circle (1.0pt); \fill[red!70!black] (J1) circle (1.2pt); \fill[red!70!black] (J2) circle (1.0pt); \fill[blue!60!black] (B) circle (1.2pt); % labels \node[anchor=north east,inner sep=2pt] at (J) {$J$}; \node[anchor=north,inner sep=3pt] at (J1) {$J_1$}; \node[anchor=north west,inner sep=2.5pt,blue!50!black] at (B) {vertex}; \node[teal!35!black] at (2.45,1.85,\h) {$\sigma>0$}; \node[orange!45!black] at (3.6,2.9,\h) {$F$}; \node[red!60!black,anchor=west,inner sep=1pt] at (0.05,2.5,\h) {$\sigma\le0$}; \node[gray!60!black] at (2.1,0,0.55) {$\mathcal R$}; \end{tikzpicture} \end{document}