5

What does numbers in 3-tuple mean? For example, starting point, terminal point and length.

By changing numbers in codes I found that left 3 tuple in the left parenthesis means starting point, and the 3-tuple in the right parenthesis means terminal point. And the second component of 3-tuple means vertical location; the first component means horizontal location, but when I change the third component, what I learned from changin the first and the second is not definite. The arrow becomes shorter or longer and the vertical and horizontal location also seem to change.

For example, if I change the second component of 3 tuple in the left parenthesis from 0 to 1, the starting point goes up.

\draw [axisline] (-3,0,0) -- (3,0,0) node[right]{$x$};
\draw [axisline] (-3,1,0) -- (3,0,0) node[right]{$the second component changed from 0 to 1$};

enter image description here

\documentclass{article}   
\usepackage{tikz}  
\begin{document}  
\begin{tikzpicture}[axisline/.style={very thick,-stealth}, rotate around y=10,]  
\draw [axisline] (-3,0,0) -- (3,0,0) node[right]{$x$};  
\draw [axisline] (0,-3,0) -- (0,3,0) node[left]{$y$};  
\draw [axisline, cyan] (0,0,0) -- (0,0,2) node[right]{$z$};  
\end{tikzpicture}  
\end{document}
3
  • 3
    They are x, y and z values for a 3D coordinate system
    – Ignasi
    Apr 8, 2016 at 6:48
  • @Ignasi So the third component in 3 tuple means z value? But why x, y values as well as z value seem to change when I change the third component in the 3-tuple?
    – buzzee
    Apr 8, 2016 at 6:59
  • 1
    you are using a 2D printer so z direction is approximated by projection into x and y Apr 8, 2016 at 7:05

1 Answer 1

5

Some example with your code.

Let's start drawing the unit vectors of our coordinate system:

\documentclass[tikz,border=2mm]{standalone}   
\usepackage{tikz}  
\begin{document}  
\begin{tikzpicture}[axisline/.style={very thick,-stealth}]  

\draw[axisline] (0,0,0)--(1,0,0) node[right]{$x$};
\draw[axisline] (0,0,0)--(0,1,0) node[above]{$y$};
\draw[axisline] (0,0,0)--(0,0,1) node[below left]{$z$};

\end{tikzpicture}  
\end{document}

enter image description here

Now you can change any of this units and see what happens.

\documentclass[tikz,border=2mm]{standalone}   
\usepackage{tikz}  
\begin{document}  
\begin{tikzpicture}[axisline/.style={very thick,-stealth}]  

\draw[axisline] (0,0,0)--(1,0,0) node[right]{$x$};
\draw[axisline] (0,0,0)--(0,1,0) node[above]{$y$};
\draw[axisline] (0,0,0)--(0,0,1) node[below left]{$z$};

\draw[red] (0,0,0)--(3,0,0); 
\draw[blue] (0,0,0)--(0,3,0); 
\draw[green] (0,0,0)--(0,0,-4); 
\end{tikzpicture}  
\end{document}

enter image description here

If default 3D representation doesn't fit your needs, you can adjust it defining new x, y, z unit vectors. More details in pgfmanual section "25.2 The XY- and XYZ-Coordinate Systems".

\documentclass[tikz,border=2mm]{standalone}   
\usepackage{tikz}  
\begin{document}  
\begin{tikzpicture}[axisline/.style={very thick,-stealth}, x={(0.867,0.5)}, z={(0.5,-.867)}]  

\draw[axisline] (0,0,0)--(1,0,0) node[right]{$x$};
\draw[axisline] (0,0,0)--(0,1,0) node[above]{$y$};
\draw[axisline] (0,0,0)--(0,0,1) node[below left]{$z$};

\draw[red] (0,0,0)--(3,0,0); 
\draw[blue] (0,0,0)--(0,3,0); 
\draw[green] (0,0,0)--(0,0,-4); 
\end{tikzpicture}  
\end{document}

enter image description here

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.