Spherical shell using tikz

Question

How can I draw a spherical shell of a certain thickness using tikz?

I have found this question where somebody was asking about drawing one sphere inside another, which is surely related to this one.

Drawing Sphere to represent a black hole

Any help?

Answer 1

I can only guess.

\documentclass[tikz,border=3.14mm]{standalone}
\usepackage{tikz-3dplot}
\usetikzlibrary{3d}
% https://tex.stackexchange.com/a/12033/121799
\tikzset{reverseclip/.style={insert path={(current bounding box.north
        east) rectangle (current bounding box.south west)}}}
\begin{document}
\tdplotsetmaincoords{110}{-30}
\begin{tikzpicture}[tdplot_main_coords]
\pgfmathsetmacro{\Radius}{4}
\pgfmathsetmacro{\radius}{3.6}
\path[tdplot_screen_coords] (0,0) circle (\Radius);
\begin{scope}
\clip plot[variable=\x,domain=0:90] (xyz spherical cs:radius=\Radius,latitude=00,longitude=\x)
-- plot[variable=\x,domain=0:90] (xyz spherical cs:radius=\Radius,latitude=\x,longitude=90)
-- plot[variable=\x,domain=90:0] (xyz spherical cs:radius=\Radius,latitude=\x,longitude=0)
[reverseclip];
\shade[tdplot_screen_coords,ball color=gray,opacity=0.5] (0,0) circle (\Radius);
\end{scope}
\fill[top color=gray!80,bottom color=gray!60]
plot[variable=\x,domain=90:0] (xyz spherical cs:radius=\radius,latitude=00,longitude=\x)
-- plot[variable=\x,domain=90:0] (xyz spherical cs:radius=\radius,latitude=\x,longitude=90)
-- plot[variable=\x,domain=0:90] (xyz spherical cs:radius=\radius,latitude=\x,longitude=0);
\draw[fill=gray!10] plot[variable=\x,domain=0:90] (xyz spherical cs:radius=\Radius,latitude=00,longitude=\x)
-- plot[variable=\x,domain=90:0] (xyz spherical cs:radius=\radius,latitude=00,longitude=\x)
-- cycle;
\draw[fill=gray!30] plot[variable=\x,domain=0:90] (xyz spherical cs:radius=\Radius,latitude=\x,longitude=90)
-- plot[variable=\x,domain=90:0] (xyz spherical cs:radius=\radius,latitude=\x,longitude=90)
-- cycle;
\draw[fill=gray!70] plot[variable=\x,domain=90:0] (xyz spherical cs:radius=\Radius,latitude=\x,longitude=0)
-- plot[variable=\x,domain=0:90] (xyz spherical cs:radius=\radius,latitude=\x,longitude=0)
-- cycle;
\end{tikzpicture}
\end{document}

ADDENDUM: Just for fun (because @Raaja teased me). The code is taken from the codes that were used in the 2018 Christmas extravaganza.

\documentclass[tikz,border=3.14mm]{standalone}
\usepackage{tikz-3dplot}
\usetikzlibrary{3d}
\usetikzlibrary{calc,ducks,marmots}
\usepgfmodule{nonlineartransformations}
\makeatletter
% from https://tex.stackexchange.com/a/434247/121799
\tikzdeclarecoordinatesystem{sphere}{
    \tikz@scan@one@point\relax(#1)
    \spheretransformation
}
% 
\def\spheretransformation{% similar to the pgfmanual section 103.4.2
\pgfmathsincos@{\pgf@sys@tonumber\pgf@x}%
\pgfmathsetmacro{\relX}{\the\pgf@x/28.3465}%
\pgfmathsetmacro{\relY}{\the\pgf@y/28.3465}%min(max(
\pgfmathsetmacro{\myx}{28.3465*\Radius*cos(min(max((\relY/\Radius)*(180/pi),-90),90))*sin(min(max((\relX/\Radius)*cos(min(max((\relY/\Radius)*(180/pi),-90),90))*(180/pi),-90),90))}
\pgfmathsetmacro{\myy}{28.3465*\Radius*sin(min(max((\relY/\Radius)*(180/pi),-90),90))}%\typeout{(\relX,\relY)->(\myx,\myy)}%
\pgf@x=\myx pt%
\pgf@y=\myy pt%
} 
\makeatother

\tikzfading[name=highlight,inner color=transparent!0,outer color=transparent!100]

% https://tex.stackexchange.com/a/12033/121799
\tikzset{reverseclip/.style={insert path={(current bounding box.north
        east) rectangle (current bounding box.south west)}}}
\begin{document}
\tdplotsetmaincoords{110}{-30}
\foreach \X in {2,1.9,...,-4}
{\begin{tikzpicture}[declare function={
myx(\x,\y,\r)=\r*cos((\y/\r)*(180/pi))*sin((\x/\r)*cos((\y/\r)*(180/pi))*(180/pi));
myy(\x,\y,\r)=\r*sin((\y/\r)*(180/pi));},tdplot_main_coords]
 \pgfmathsetmacro{\Radius}{4}
 \pgfmathsetmacro{\radius}{3.6}
 \path[tdplot_screen_coords] (0,0) circle (\Radius);
 \begin{scope}
  \clip plot[variable=\x,domain=0:90] (xyz spherical cs:radius=\Radius,latitude=00,longitude=\x)
  -- plot[variable=\x,domain=0:90] (xyz spherical cs:radius=\Radius,latitude=\x,longitude=90)
  -- plot[variable=\x,domain=90:0] (xyz spherical cs:radius=\Radius,latitude=\x,longitude=0)
  [reverseclip];
  \shade[tdplot_screen_coords,ball color=gray,opacity=0.5] (0,0) circle (\Radius);
 \end{scope}
 \draw[fill=gray!10] plot[variable=\x,domain=0:90] (xyz spherical cs:radius=\Radius,latitude=00,longitude=\x)
 -- plot[variable=\x,domain=90:0] (xyz spherical cs:radius=\radius,latitude=00,longitude=\x)
 -- cycle;
 \draw[fill=gray!30] plot[variable=\x,domain=0:90] (xyz spherical cs:radius=\Radius,latitude=\x,longitude=90)
 -- plot[variable=\x,domain=90:0] (xyz spherical cs:radius=\radius,latitude=\x,longitude=90)
 -- cycle;
 \draw[fill=gray!70] plot[variable=\x,domain=90:0] (xyz spherical cs:radius=\Radius,latitude=\x,longitude=0)
 -- plot[variable=\x,domain=0:90] (xyz spherical cs:radius=\radius,latitude=\x,longitude=0)
 -- cycle;
 \clip
 plot[variable=\x,domain=90:0] (xyz spherical cs:radius=\radius,latitude=00,longitude=\x)
 -- plot[variable=\x,domain=90:0] (xyz spherical cs:radius=\radius,latitude=\x,longitude=90)
 -- plot[variable=\x,domain=0:90] (xyz spherical cs:radius=\radius,latitude=\x,longitude=0);
 \begin{scope}[tdplot_screen_coords]
  \shade[inner color=red, outer color=red!50!black] (0,0) circle (\radius);
  \begin{scope}[transform shape nonlinear=true]
   \pgftransformnonlinear{\spheretransformation}
   \marmot[scale=2.5,xshift=\X*1cm,yshift=-1.2cm];
  \end{scope}
  \shade[ball color=red,opacity=0.3] (0,0) circle (\radius);
  \fill[white,path fading=marmot@blush] (-.35*\radius,.5*\radius) circle (.3*\radius);
  \fill[orange!50!yellow] (0,3.9) ellipse (0.7 and 0.3);
  \draw[orange!50!yellow, ultra thick] (0.45,4.1) arc [start angle=0, end angle=180,radius=0.45];
 \end{scope}
\end{tikzpicture}}
\end{document}

The spurious lines do not appear on the pdf, nor on the mp4 that can be generated using this chain.