Differential Volume in Cylindrical Coordinates

For more figures related to the definition of coordinate systems, please have a look at the “coordinates” tag.

Edit and compile if you like:

\documentclass[border=3pt]{standalone}

\usepackage{tikz}  
\usepackage{tikz-3dplot} 

%Cylindrical Coordinate
\newcommand{\cylindricalcoordinate}[4]{%
\coordinate (#4) at ({#1*cos(#2)},{#1*sin(#2)},{#3});%
\coordinate (#4xy) at ({#1*cos(#2)},{#1*sin(#2)},0);%
}

\begin{document}

%Axis Angles
\tdplotsetmaincoords{70}{110}

%Macros
\pgfmathsetmacro{\rvec}{5}
\pgfmathsetmacro{\phivec}{45}
\pgfmathsetmacro{\zvec}{4}

\pgfmathsetmacro{\drvec}{1.5}
\pgfmathsetmacro{\dphivec}{20}
\pgfmathsetmacro{\dzvec}{1}

%Layers
\pgfdeclarelayer{background}
\pgfdeclarelayer{foreground}

\pgfsetlayers{background, main, foreground}

\begin{tikzpicture}[tdplot_main_coords]

%Coordinates
\coordinate (O) at (0,0,0);
%%
\cylindricalcoordinate{\rvec}{\phivec}{\zvec}{A}
\cylindricalcoordinate{\rvec}{\phivec}{(\zvec+\dzvec)}{B}
\cylindricalcoordinate{\rvec}{(\phivec+\dphivec)}{\zvec}{C}
\cylindricalcoordinate{\rvec}{(\phivec+\dphivec)}{(\zvec+\dzvec)}{D}
%%
\cylindricalcoordinate{(\rvec+\drvec)}{\phivec}{\zvec}{A'}
\cylindricalcoordinate{(\rvec+\drvec)}{\phivec}{(\zvec+\dzvec)}{B'}
\cylindricalcoordinate{(\rvec+\drvec)}{(\phivec+\dphivec)}{\zvec}{C'}
\cylindricalcoordinate{(\rvec+\drvec)}{(\phivec+\dphivec)}{(\zvec+\dzvec)}{D'}
%%%Nodes
%\node at (A) {A};
%\node at (B) {B};
%\node at (C) {C};
%\node at (D) {D};
%\node at (A') {A'};
%\node at (B') {B'};
%\node at (C') {C'};
%\node at (D') {D'};

%Axis
\begin{pgfonlayer}{background}
	\draw[thick,-latex] (0,0,0) -- (6,0,0) node[pos=1.1]{$x$};
	\draw[thick,-latex] (0,0,0) -- (0,6,0) node[pos=1.05]{$y$};
	\draw[thick,-latex] (0,0,0) -- (0,0,7) node[pos=1.05]{$z$};
\end{pgfonlayer}

%Vectors
\begin{pgfonlayer}{main}
	\draw[blue, thick] (O) -- (A);
	\draw[thick] (O) -- (Axy) node [pos=0.6, below left] {$\varpi$};
	\draw (A) -- ($(A)-(Axy)$) node [left] {$z$};
	\draw (B) -- ($(A)-(Axy)+(0,0,\dzvec)$) node [left] {$z+\mathrm{d}z$};
	\draw (D) -- ($(A)-(Axy)+(0,0,\dzvec)$);
\end{pgfonlayer}
\begin{pgfonlayer}{background}
	\draw[dashed] (C) -- ($(A)-(Axy)$) node [left] {$z$};
\end{pgfonlayer}

%Help Lines
\begin{pgfonlayer}{background}
	\draw (A) -- (Axy);
	\draw (A') -- (A'xy);
	\draw[thick] (Axy) -- (A'xy) node [pos=0.6, below left] {$\mathrm{d}\varpi$};
	%
	\draw (O) -- (D'xy);
	\draw[dashed] (C) -- (Dxy);	
	\draw (C') -- (C'xy);
	%%Arcs
	\tdplotdrawarc{(0,0,0)}{\rvec}{\phivec}{\phivec+\dphivec}{}{}
	\tdplotdrawarc{(0,0,0)}{\rvec+\drvec}{\phivec}{\phivec+\dphivec}{}{}
\end{pgfonlayer}

%Angles
\begin{pgfonlayer}{foreground}
	%Phi, dPhi
	\tdplotdrawarc[-stealth]{(O)}{0.9}{0}{\phivec}{anchor=north}{$\phi$}
	\tdplotdrawarc[-stealth]{(O)}{1.5}{\phivec}{\phivec + \dphivec}{}{}
	\node at (1.4,1.9,0) {$\mathrm{d}\phi$};	
\end{pgfonlayer}

%Differential Volume

%%Lines
\begin{pgfonlayer}{foreground}
	\draw[thick] (A) -- (B) -- (B') -- (A') -- cycle node [midway, below] {$\mathrm{d}\varpi$};
	\draw[thick] (D) -- (D') -- (C') node [midway, right] {$\mathrm{d}z$};
\end{pgfonlayer}
\begin{pgfonlayer}{background}
	\draw[thick, dashed] (C') -- (C) -- (D);
\end{pgfonlayer}

%%Curved
\begin{pgfonlayer}{background}
	\tdplotdrawarc[thick, dashed]{(0,0,\zvec)}{\rvec} {\phivec}{\phivec+\dphivec}{}{}
\end{pgfonlayer}
\begin{pgfonlayer}{foreground}
	\tdplotdrawarc[thick]{(0,0,\zvec+\dzvec)}{\rvec} {\phivec}{\phivec+\dphivec}{}{}
	\node at (2.4,3.4,\zvec+\dzvec) {$\varpi\mathrm{d}\phi$};
	\tdplotdrawarc[thick]{(0,0,\zvec+\dzvec)}{\rvec+\drvec} {\phivec}{\phivec+\dphivec}{}{}
	\tdplotdrawarc[thick]{(0,0,\zvec)}{\rvec+\drvec} {\phivec}{\phivec+\dphivec}{}{}
\end{pgfonlayer}

%%Fill Color
\begin{pgfonlayer}{main}
	%Front
	\fill[black, opacity=0.15] (B) to (B') to[bend right=4] (D') to (D) to[bend left=4] cycle;
	\fill[black, opacity=0.6] (B') to[bend right=4] (D') to (C') to[bend left=4] (A') to cycle;
	\fill[black, opacity=0.4] (B) to (B')  to (A') to (A) to cycle;
\end{pgfonlayer}
\begin{pgfonlayer}{background}
	%Back
	\fill[black!50, opacity=0.5] (D) to (D') to (C') to (C) to cycle;
	\fill[black!50, opacity=0.5] (B) to[bend right=4] (D) to (C) to[bend left=4] (A) to cycle;
	\fill[black!50, opacity=0.5] (A) to (A') to[bend right=4] (C') to (C) to[bend left=4] cycle;
\end{pgfonlayer}


\end{tikzpicture}

\end{document}