I would like to draw a 2D network on the surface of a light-grey non-transparent sphere. In the actual fact, the network represents a 2D square lattice composed of many balls and springs as proposed below in TikZ code (by courtesy of @marmot). The idea is to have a spherical elastic membrane capturing an ideal gas inside. The lattice essentially symbolizes the microscopic structure of the membrane.

This question has its roots in the original one:

Drawing a 2D square lattice (springs + balls) on a convex surface

Thank you greatly for the help in advance.

\clip (-1,-1) rectangle (11,11);
\foreach \X in {-2,0,...,10}
{\foreach \Y in {-2,0,...,10}
 {\draw[decorate,decoration={coil,aspect=0.5,amplitude=1.5mm, segment
length=1.5mm}] (\X,\Y) -- ++(0,2) -- ++(2,0);
color=blue,outer color=black] at (\X,\Y) {+};}}
  • 1
    Can you please add a sketch of what you want to achieve? – marmot Dec 18 '18 at 11:52
  • The same as the picture from @marmot code (i.stack.imgur.com/Kz0Im.png), but spanned across the entire sphere which is coloured in non-transparent light-grey. – Savchenko Dec 18 '18 at 13:26

Here is a first attempt: solid sphere plus different plot marks. Everything else is as in the last code of this answer.

% Declare nice sphere shading: http://tex.stackexchange.com/a/54239/12440

% Style to set TikZ camera angle, like PGFPlots `view`
\tikzset{viewport/.style 2 args={

% Styles to plot only points that are before or behind the sphere.
\pgfplotsset{only foreground/.style={
    restrict expr to domain={rawx*\CameraX + rawy*\CameraY + rawz*\CameraZ}{-0.05:100},
\pgfplotsset{only background/.style={
    restrict expr to domain={rawx*\CameraX + rawy*\CameraY + rawz*\CameraZ}{-100:0.05}

% Automatically plot transparent lines in background and solid lines in foreground
    \addplot3[#1,only background, opacity=0.25] #2;
    \addplot3[#1,only foreground] #2;

% attempt to do similar things for discrete plots
    %\addplot3[#1,only background,gray!50] #2;
    \addplot3[#1,only foreground] #2;


\tikzset{spring/.style={decorate,decoration={coil,aspect=0.5,amplitude=1.5mm, segment
% pgfmanual p. 1087
 {color(0bp)=(blue!100!black); color(9bp)=(blue!90!black);
 color(18bp)=(blue!70!black); color(25bp)=(blue!50!black); color(50bp)=(black)}

    % Compute camera unit vector for calculating depth
    \path[use as bounding box] (-\R,-\R) rectangle (\R,\R); % Avoid jittering animation
    % Draw a nice looking sphere
        \clip (0,0) circle (\R);
        \begin{scope}[transform canvas={rotate=-20}]
            \shade [ball color=white] (0,0.5) ellipse (\R*1.8 and \R*1.5);
        hide axis,
        view={\ViewAzimuth}{\ViewElevation},     % Set view angle
        every axis plot/.style={very thin},
        disabledatascaling,                      % Align PGFPlots coordinates with TikZ
        anchor=origin,                           % Align PGFPlots coordinates with TikZ
        viewport={\ViewAzimuth}{\ViewElevation}, % Align PGFPlots coordinates with TikZ
        % plot latitude circles
        {\addFGBGSampleplot[spring,domain=0:2*pi, samples=51, samples y=1]
        ({\R*cos(#1)*cos(deg(x))}, {\R*cos(#1)*sin(deg(x))}, {\R*sin(#1)});}
        % plot longitude circles
        {\addFGBGSampleplot[spring,domain=0:2*pi, samples=51, samples y=1]
        ({\R*cos(#1)*cos(deg(x))}, {\R*sin(#1)*cos(deg(x))}, {\R*sin(deg(x))});     
        % plot longitude circles
        {\addFGBGSampleplot[only marks,mark=interesting,samples at={-75,-45,...,75}]
        ({\R*cos(#1)*cos(x)}, {\R*sin(#1)*cos(x)}, {\R*sin(x)});        

enter image description here

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