I'd like to make the markings of the angles of a triangle, in three dimensional space, automatically, using the \tdplotdrawpolytopearc
.
I tried something like:
\documentclass{article}
\usepackage{tikz}
\usepackage{tikz-3dplot}
\begin{document}
\tdplotsetmaincoords{80}{110}
\begin{tikzpicture}[tdplot_main_coords,>=stealth']
\coordinate (A) at (3,1,1);
\coordinate (B) at (8,7,1);
\coordinate (C) at (3,6,3);
\draw[-] (A) -- (B) -- (C) -- cycle;
\tdplotdefinepoints(C)(A)(B);
\tdplotdrawpolytopearc[thick]{0.6}{}{$\alpha$}
\tdplotdefinepoints(A)(B)(C);
\tdplotdrawpolytopearc[thick]{0.6}{}{$\beta$}
\tdplotdefinepoints(B)(C)(A);
\tdplotdrawpolytopearc[thick]{0.6}{}{$\gamma$}
\end{tikzpicture}
\end{document}
But the command \tdplotdefinepoints(B)(A)(C);
does not work.
It works only if the vertices are described explicitly, as in
\tdplotdefinepoints(8,7,1)(3,6,3)(3,1,1);
In the plane, I don't have ploblem. See this solutions.
Could someone please offer some help?
It will help a lot.
But now I have another problem.
In my case a point is calculated from others.
For example, we can take the midpoint, $M$, $0.5*(B) + 0.5*(C)$
on the side BC.
How to mark the angle between the sides AC and AM?
Something like
\ptdedef\temp{\noexpand\tdplotdefinepoints(\ptC)(\ptB)($0.5*(A)+0.5*(B)$);} \temp
did not work.