# How can I draw a sphere circumsribed a pyramid?

From here Using Tikz, is it possible to draw a cube within a sphere? I want to draw a circumsribed sphere with centre at O(1,1,1) and radius R = sqrt(3). I tried

\documentclass[12pt]{standalone}
\usepackage{tikz}
\usepackage{tikz-3dplot}
\usetikzlibrary{arrows,calc}
\begin{document}
\tdplotsetmaincoords{60}{110}
\begin{tikzpicture}[scale=1]
\def\R{sqrt(3)}
\coordinate (O) at (1,1,1);
\fill[ball color=cyan!10, opacity=1.0] (O) circle (\R); % 3D lighting effect
\begin{scope}[tdplot_main_coords, shift={(1,1,1)}, rotate=0]
\path
coordinate (A) at (0,0,0)
coordinate (B) at (2,0,0)
coordinate (C) at (2,2,0)
coordinate (D) at (0,2,0)
coordinate (S) at (0,0,2)
coordinate (O) at (1,1,1);
\draw[ dashed]
(A)--(S) (A)--(B)
(A)--(D)
;

\draw [fill opacity=0.4,fill=green!80!blue] (S) -- (B) -- (C) -- cycle;
\draw [fill opacity=0.4,fill=orange!80!blue] (S) -- (C) -- (D) -- cycle;

\foreach \v/\position in {A/below,B/below,C/below,D/right,S/above,O/below} {
\draw[fill=black] (\v) circle (0.7pt) node [\position=0.2mm] {$\v$};
}
\end{scope}
\end{tikzpicture}
\end{document}


My result is not correct. How can I repair it?

• Do you want the sphere circumscribed by the pyramid or the pyramid circumscribed by the sphere? But you also only have a circle outside the scope of the 3D coordinates, so it is using the usual coordinate system and not the transformed ones. – cfr Jun 5 '17 at 1:40
• I want the sphere circumscribed by the pyramid . – minhthien_2016 Jun 5 '17 at 1:45
• Sorry about the bad advice earlier. I confused \fill with \node. – John Kormylo Jun 6 '17 at 14:27
• You can delete comments. The button is hidden at the very end of the line (after edit). – John Kormylo Jun 6 '17 at 15:12

One can also use tdplot_screen-coords and on background layer. This could prove more useful it you intend to use more than one sphere.

\documentclass[12pt]{standalone}
\usepackage{tikz}
\usepackage{tikz-3dplot}
\usetikzlibrary{arrows,calc,backgrounds}
\begin{document}
\tdplotsetmaincoords{60}{110}
\begin{tikzpicture}[tdplot_main_coords]
\path
coordinate (A) at (0,0,0)
coordinate (B) at (2,0,0)
coordinate (C) at (2,2,0)
coordinate (D) at (0,2,0)
coordinate (S) at (0,0,2)
coordinate (O) at (1,1,1);

\draw[ dashed] (A)--(S) (A)--(B) (A)--(D);
\draw [fill opacity=0.4,fill=green!80!blue] (S) -- (B) -- (C) -- cycle;
\draw [fill opacity=0.4,fill=orange!80!blue] (S) -- (C) -- (D) -- cycle;

\foreach \v/\position in {A/below,B/below,C/below,D/right,S/above,O/below} {
\draw[fill=black] (\v) circle (0.7pt) node [\position=0.2mm] {$\v$};
}

\begin{scope}[tdplot_screen_coords, on background layer]
\pgfmathsetmacro{\R}{sqrt(3)}%
\fill[ball color=cyan!10, opacity=1.0] (O) circle (\R); % 3D lighting effect
\end{scope}
\end{tikzpicture}
\end{document}


• How can draw a circle passing throught four points A, B, C, D? – minhthien_2016 Jun 6 '17 at 14:55
• I hope, you will find a solution for my question. – minhthien_2016 Jun 6 '17 at 15:39
• tikz-3d always draws circles in the xy plane. The center is at (1,1,0) and the radius is sqrt(2). – John Kormylo Jun 6 '17 at 15:50
• Style of arc B, C, D is dashed. How can I draw it? – minhthien_2016 Jun 7 '17 at 0:03
• Arc BCD is easy. In the xy plane B is at -45 degrees and D is at 135 degrees relative to the center. If you want to make the arc which is between the points where the two circles intersect solid, that is a more interesting problem. – John Kormylo Jun 7 '17 at 12:22

I did so.

\documentclass[border=2mm12pt]{standalone}
\usepackage{tikz}
\usepackage{tikz-3dplot}
\usetikzlibrary{arrows,calc}
\begin{document}
\tdplotsetmaincoords{60}{110}
\begin{tikzpicture}[scale=2]
\def\R{sqrt(3)}
\coordinate (O) at (0,0,0);
\fill[ball color=cyan!10, opacity=1.0]  (O) circle (\R); % 3D lighting effect
\begin{scope}[tdplot_main_coords, shift={(0,0)}, rotate=0]
\path
coordinate (A) at (-1,-1,-1)
coordinate (B) at (1,-1,-1)
coordinate (C) at (1,1,-1)
coordinate (D) at (-1,1,-1)
coordinate (S) at (-1,-1,1);
\draw[ dashed]
(A)--(S) (A)--(B)
(A)--(D)
;
\draw [fill opacity=0.4,fill=green!80!blue] (S) -- (B) -- (C) -- cycle;
\draw [fill opacity=0.4,fill=orange!80!blue] (S) -- (C) -- (D) -- cycle;
\foreach \v/\position in {A/below,B/below,C/below,D/right,S/above,O/right} {
\draw[fill=black] (\v) circle (0.7pt) node [\position=0.2mm] {$\v$};
}
\end{scope}
\end{tikzpicture}
\end{document}


• Is this an answer? What 'so' did you? – cfr Jun 8 '17 at 23:31
• @cfr This is my answer. My method have to transform the sphere so that center of sphere is origion. When I saw John Kormylo, I saw that, his method faster than my solution. – minhthien_2016 Jun 9 '17 at 0:11