Balloon shape with tangent in TikZ

Question

I want to draw the attached figure that I did in power point in Latex, I can't figure out an easy way to draw the tangent and I want to draw the balloon shape as 3d plot

\documentclass[tikz,border=5pt]{standalone}
\begin{document}
\begin{tikzpicture}[scale=0.5]
   \draw[rotate=180] (-2,0.25)--++(8,0);
  \draw[rotate=180, fill=gray!30] (2,0.25) .. controls (9,6) and (-5,6) .. (2,0.25);
\begin{scope}[xshift=6cm, yshift=-10cm]
  \def\rx{4}    % horizontal radius of the ellipse
  \def\ry{0.5}  % vertical radius of the ellipse
  \def\z{2}     % distance from center of ellipse to origin
\pgfmathparse{asin(\ry/\z)}
  \let\angle\pgfmathresult
\coordinate (h) at (0, \z);
  \coordinate (O) at (0, 0);

  \coordinate (A) at ({-\rxcos(\angle)}, {\z-\rysin(\angle)});
  \coordinate (B) at ({\rxcos(\angle)}, {\z-\rysin(\angle)});
   \coordinate (C) at (3, 2);
\draw[fill=gray!50] (A) -- (O) -- (B) -- cycle;
  \draw[fill=gray!30] (h) ellipse ({\rx} and {\ry});
  \end{scope}
\end{tikzpicture}
\end{document}

Irregular shapes are always more difficult than regular shapes. If d is tangent at the top, you need a cone which morphs into an off-center sphere. — John Kormylo, Jul 20 '22 at 13:16

antshar · Accepted Answer · 2022-07-21T09:01:28.460

\documentclass[tikz,border=5pt]{standalone}
\begin{document}
\usetikzlibrary{decorations.markings}
\begin{tikzpicture}[scale=0.5]
   \draw[rotate=180] (-2,0)--++(8,0);
   \draw[ball color=gray!5, looseness=1.5] (0,0) to[out=-20,in=0] nodesloped, pos=0.3{} (0,-3) to[out=180, in=180+20] nodesloped, fill=black, inner xsep=40pt, inner ysep=0, yscale=0.4, pos=0.9{} cycle;
\begin{scope}[xshift=6cm, yshift=-10cm]
  \def\rx{2.5}    % horizontal radius of the ellipse
  \def\ry{0.3}  % vertical radius of the ellipse
  \def\z{1.5}     % distance from center of ellipse to origin
\pgfmathparse{asin(\ry/\z)}
  \let\angle\pgfmathresult
\coordinate (h) at (0, \z);
  \coordinate (O) at (0, 0);

  \coordinate (A) at ({-\rxcos(\angle)}, {\z-\rysin(\angle)});
  \coordinate (B) at ({\rxcos(\angle)}, {\z-\rysin(\angle)});
  \coordinate (C) at (3, 2);
  \draw[left color=gray!50,right color=white] (A) -- (O) -- (B) -- cycle;
  \draw[fill=gray!30] (h) ellipse ({\rx} and {\ry});
\end{scope}
\draw[<->, shorten >= -23pt] (O) -- (P);
\end{tikzpicture}
\end{document}

Look at this question: How to draw tangent line of an arbitrary point on a path in TikZ as well.

@Diana for example via yscale to shrink it down. See the edited post. — antshar, Jul 21 '22 at 09:01

Balloon shape with tangent in TikZ

1 Answers1