LaTeX forum ⇒ General ⇒ How can I draw this cylinder Topic is solved

[Tran Van Toan]

I want to draw this picture, but I can't. My difficult is how can I make points on two circles of cylinder.

[Stefan Kottwitz]

Hi,

can you post the code here, that you already have?

how can I make points on two circles of cylinder

If it's just the points, we don't have to work on drawing a cylinder etc. if you might have that already, that's why I ask for the code.

Stefan

[Tran Van Toan]

My cylinder.

Code: [Select all] [Expand/Collapse] [Download] ({untitled.tex}) Open in Overleaf

\documentclass[border=5]{standalone}
\usepackage{tikz}
\usepackage{tkz-euclide}
\usetkzobj{all}
\usetikzlibrary{shadings}
\begin{document}
\begin{tikzpicture}
\def\R{2}
  \fill[top color    = gray!50!black,
        bottom color = gray!10,
        middle color = gray,
        shading      = axis,
        opacity      = 0.25]
    (0,0) circle (\R cm and 0.5cm);
  \fill[left color   = gray!50!black,
        right color  = gray!50!black,
        middle color = gray!50,
        shading      = axis,
        opacity      = 0.25]
    (\R,0) -- (\R,2*\R)  arc (360:180:\R cm and 0.5cm)
          -- (-\R,0) arc (180:360:\R cm and 0.5cm);
  \fill[top color    = gray!90!,
        bottom color = gray!2,
        middle color = gray!30,
        shading      = axis,
        opacity      = 0.25]
    (0,2*\R) circle (\R cm and 0.5cm);
  \draw (-\R,2*\R) -- (-\R,0) arc (180:360:\R cm and 0.5cm)
               -- (\R,2*\R) ++ (-\R,0) circle (\R cm and 0.5cm);
  \draw[densely dashed] (-\R,0) arc (180:0:\R cm and 0.5cm);
 
 \end{tikzpicture}
\end{document}

[Tran Van Toan]

I tried

Code: [Select all] [Expand/Collapse] [Download] ({untitled.tex}) Open in Overleaf

\documentclass[border=5]{standalone}
\usepackage{tikz}
\usepackage{tkz-euclide}
\usetkzobj{all}
\usetikzlibrary{shadings}
\begin{document}
\begin{tikzpicture}
\def\R{2}
\def\a{1}
\def\z{1}
\def\h{2*\R}
  \fill[top color    = gray!50!black,
        bottom color = gray!10,
        middle color = gray,
        shading      = axis,
        opacity      = 0.25]
    (0,0) circle (\R cm and \a cm);
  \fill[left color   = gray!50!black,
        right color  = gray!50!black,
        middle color = gray!50,
        shading      = axis,
        opacity      = 0.25]
    (\R,0) -- (\R,\h)  arc (360:180:\R cm and \a cm)
          -- (-\R,0) arc (180:360:\R cm and \a cm);
  \fill[top color    = gray!90!,
        bottom color = gray!2,
        middle color = gray!30,
        shading      = axis,
        opacity      = 0.25]
    (0,\h) circle (\R cm and \a cm);
  \draw (-\R,\h) -- (-\R,0) arc (180:360:\R cm and \a cm)
               -- (\R,\h) ++ (-\R,0) circle (\R cm and \a cm);
  \draw[densely dashed] (-\R,0) arc (180:0:\R cm and \a cm);
\coordinate (B) at (0,0);
\coordinate (A) at ($(B)+(0,\h)$);
\coordinate (E) at (-\R,\h);
\coordinate (F) at (\R,\h);
\coordinate (G) at (-\R,0);
\coordinate (H) at (\R,0);
\coordinate (C) at ($(B) + (225:{\R} and {\a})$);
\coordinate (D) at ($(C)+(0,\h)$);
\tkzFillPolygon[pattern=north west lines](A,B,C,D)
\tkzDrawSegments[](A,D D,C E,G F,H)
\tkzDrawSegments[dashed](A,B B,C)
\tkzDrawPoints[fill = black,size = 2 pt](A,B,C,D)
 
\tkzLabelPoints[right](A,B)
\tkzLabelPoints[above](D)
\tkzLabelPoints[below](C)
 \end{tikzpicture}
\end{document}

And got

[Tran Van Toan]

But not good at here. How can I repair?

[Stefan Kottwitz]

Looks already good! Change this line

\tkzDrawSegments[](A,D D,C E,G F,H)

to that one, removing the unnecessary two last segments:

\tkzDrawSegments[](A,D D,C)

Stefan

[Tran Van Toan]

Thank you very much.