[Tex/LaTex] Connecting an arced path in TikZ

arctikz-pgf

I'm trying to draw an octant of a sphere. I'm not an expert on drawing perspective, but I managed that with, among others, the arc command. With the sphere drawn I made some layers, again with the arc command, that I'd like to fill to help distuingish them from the others layers. I made a path of one of the layers, filled it but not with the expected result. The path seems closed to me, but not to TikZ. How can I close the arced path and fill it? I presume my manual finetuning of the coordinates might be the cause of the problem?

MWE

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{through,shapes}

\begin{document}
\begin{tikzpicture}
    % coordinaten
    \coordinate (m) at (0,4,0);
    % assen
    \draw (0,0,0) -- (0,4,0); % z
    \draw (0,0,0) -- (4,0,0); % x
    \draw (0,0,0) -- (0,0,4.65); % y
    % sfeer
    \draw (4,0,0) arc (0:116.5:4cm and -2cm);
    \draw (4,0,0) arc (0:90:4cm and 4cm);
    \draw (0,4,0) arc (90:206.5:2cm and 4cm);
    \node[draw,circle through={(m)}] (c) at (0,0,0) {};
    % fotosfeer
    \draw (3.875,0,0) arc (0:115.8:3.875cm and -1.875cm);
    \draw (3.875,0,0) arc (0:90:3.875cm and 3.875cm);
    \draw (0,3.875,0) arc (90:205.8:1.875cm and 3.875cm);
    % convenctie zone
    \draw (2,0,0) arc (0:116.5:2cm and -1cm);
    \draw (2,0,0) arc (0:90:2cm and 2cm);
    \draw (0,2,0) arc (90:206.5:1cm and 2cm);
    % radiatie zone
    \draw (1,0,0) arc (0:116.5:1cm and -0.5cm);
    \draw (1,0,0) arc (0:90:1cm and 1cm);
    \draw (0,1,0) arc (90:206.5:0.5cm and 1cm);
    % fill
    \draw[fill=blue] (0,3.875,0) -- (0,2,0) (3.875,0,0) arc (0:90:3.875cm and 3.875cm) (2,0,0) arc (0:90:2cm and 2cm) (3.875,0,0) -- (2,0,0);
\end{tikzpicture}
\end{document}

Filled, yet not closed path

The part I'd like to fill is the biggest section of the xz plane, where the x axis is pointing to the east and the z axis is pointing north. With similar code I'd eventually like to fill the corresponding two parts as well.

PS: I use the circle through command instead of a plain circle node to have no problem with scaling the figure.

Best Answer

Do you mean some thing like this?

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{through,shapes}

\begin{document}
\begin{tikzpicture}
    % coordinaten
    \coordinate (m) at (0,4,0);
    % assen
    \draw (0,0,0) -- (0,4,0); % z
    \draw (0,0,0) -- (4,0,0); % x
    \draw (0,0,0) -- (0,0,4.65); % y
    % sfeer
    \draw (4,0,0) arc (0:116.5:4cm and -2cm);
    \draw (4,0,0) arc (0:90:4cm and 4cm);
    \draw (0,4,0) arc (90:206.5:2cm and 4cm);
    \node[draw,circle through={(m)}] (c) at (0,0,0) {};
    % fotosfeer
    \draw (3.875,0,0) arc (0:115.8:3.875cm and -1.875cm);
    \draw (3.875,0,0) arc (0:90:3.875cm and 3.875cm);
    \draw (0,3.875,0) arc (90:205.8:1.875cm and 3.875cm);
    %fill
    \draw[fill=blue] (0,0,0) --(0,3.875,0) arc (90:205.8:1.875cm and 3.875cm) --(0,0,0) -- (3.875,0,0)  arc (0:90:3.875cm and 3.875cm) -- (0,0,0) -- (3.875,0,0) arc (0:115.8:3.875cm and -1.875cm)--  cycle;
    % convenctie zone
    \draw (2,0,0) arc (0:116.5:2cm and -1cm);
    \draw (2,0,0) arc (0:90:2cm and 2cm);
    \draw (0,2,0) arc (90:206.5:1cm and 2cm);
    %fill
    \draw[fill=red] (0,0,0) -- (0,2,0) arc (90:206.5:1cm and 2cm) --(0,0,0) -- (2,0,0)  arc (0:90:2cm and 2cm) -- (0,0,0) -- (2,0,0) arc (0:116.5:2cm and -1cm)--  cycle;
    % radiatie zone
    \draw (1,0,0) arc (0:116.5:1cm and -0.5cm);
    \draw (1,0,0) arc (0:90:1cm and 1cm);
    \draw (0,1,0) arc (90:206.5:0.5cm and 1cm);
    %fill
    \draw[fill=green] (0,0,0) -- (0,1,0) arc (90:206.5:0.5cm and 1cm) --(0,0,0) -- (1,0,0)  arc (0:90:1cm and 1cm) -- (0,0,0) -- (1,0,0) arc (0:116.5:1cm and -0.5cm)--  cycle;

\end{tikzpicture}
\end{document}

enter image description here

Related Solutions

[Tex/LaTex] Numerical conditional within tikz keys

I am definitely unfamiliar with both beamer and tikz (do not quite get what the \only are supposed to do) but perhaps this could go in the direction you want:

\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{chains}
\newcounter{count}

% helper macro:
\long\def\GobToSemiColon #1;{}

\newcommand\myPicture{
\begin{tikzpicture}
  \begin{scope}[start chain = going below]
  \ifnum\value{count}<1 \expandafter\GobToSemiColon\fi
  \ifnum\value{count}>3 \expandafter\GobToSemiColon\fi
  \node[draw, rectangle, on chain] {display only when counter is between
    1 and 3};

  \ifnum\value{count}>-1 \expandafter\GobToSemiColon\fi
  \node[draw, rectangle, on chain] {display only when counter is
    negative}; 

  \ifnum\value{count}<100 \expandafter\GobToSemiColon\fi
  \ifnum\value{count}>200 \expandafter\GobToSemiColon\fi  
  \node[draw, rectangle, on chain] {display only if counter is between
    100 and 200};

  \ifnum\value{count}<3 \expandafter\GobToSemiColon\fi
  \ifnum\value{count}>20 \expandafter\GobToSemiColon\fi
  \node[draw, circle, on chain] {only when counter is in the range 3 to 20};
  \end{scope}
\end{tikzpicture}
}

\begin{document}
\begin{frame}
\only{\setcounter{count}{-3}\myPicture}
\only{\setcounter{count}{105}\myPicture}
\only{\setcounter{count}{39}\myPicture}
\only{\setcounter{count}{2}\myPicture}
\only{\setcounter{count}{5}\myPicture}
\end{frame}
\end{document}

beamer

[Tex/LaTex] TikZ: Drawing an arc from an intersection to an intersection

A solution which allows to draw intersection segments of any two intersections is available as tikz library fillbetween.

This library works as general purpose tikz library, but it is shipped with pgfplots and you need to load pgfplots in order to make it work:

\documentclass{standalone}

\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{fillbetween}

\begin{document}

\begin{tikzpicture}

\draw [name path=red,red] (120:1.06) circle (1.9);
%\draw [name path=yellow,yellow] (0:1.06) circle (2.12);
\draw [name path=green,green!50!black] (0:0.77) circle (2.41);
\draw [name path=blue,blue] (0:0) circle (1.06);

% substitute this temp path by `\path` to make it invisible:
\draw[name path=temp1, intersection segments={of=red and blue,sequence=L1}];
\draw[red,-stealth,ultra thick, intersection segments={of=temp1 and green,sequence=L3}];

\end{tikzpicture}

\end{document}

enter image description here

The key intersection segments is described in all detail in the pgfplots reference manual section "5.6.6 Intersection Segment Recombination"; the key idea in this case is to

create a temporary path temp1 which is the first intersection segment of red and blue, more precisely, it is the first intersection segment in the Left argument in red and blue : red. This path is drawn as thin black path. Substitute its \draw statement by \path to make it invisible.
Compute the desired intersection segment by intersecting temp1 and green and use the correct intersection segment. By trial and error I figured that it is the third segment of path temp1 which is written as L3 (L = left argument in temp1 and green and 3 means third segment of that path).

The argument involves some trial and error because fillbetween is unaware of the fact that end and startpoint are connected -- and we as end users do not see start and end point.

Note that you can connect these path segments with other paths. If such an intersection segment should be the continuation of another path, use -- as before the first argument in sequence. This allows to fill paths segments:

\documentclass{standalone}

\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{fillbetween}

\begin{document}

\begin{tikzpicture}

\draw [name path=red,red] (120:1.06) circle (1.9);
%\draw [name path=yellow,yellow] (0:1.06) circle (2.12);
\draw [name path=green,green!50!black] (0:0.77) circle (2.41);
\draw [name path=blue,blue] (0:0) circle (1.06);

% substitute this temp path by `\path` to make it invisible:
\draw[name path=temp1, intersection segments={of=red and blue,sequence=L1}];
\draw[red,fill=blue,-stealth,ultra thick, intersection segments={of=temp1 and green,sequence=L3}]  
    [intersection segments={of=temp1 and green, sequence={--R2}}]
;

\end{tikzpicture}

\end{document}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] Numerical conditional within tikz keys

[Tex/LaTex] TikZ: Drawing an arc from an intersection to an intersection

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