How does flip crossings key work?

Question

knots library supposedly has a flip crossing key which accepts a list through a modifier, or a flipcrossings macro. I first tried with the key, but it does not seem to work except for the 3d knot only. Next I tried the macro, but it was not clear where it must go. Can anyone explain how to achieve flipped crossings at every knot, not just at the last one?
documentclass{standalone}
usepackage{tikz}
usetikzlibrary{knots}

begin{document}

begin{tikzpicture}
begin{knot}[
    %draft mode=crossings ,
    clip width=3,
    flip crossing/.list={1,2,3},
    ]
    strand [ultra thick, black] (0,0) circle (1.0cm);
    strand [ultra thick, black] (1.5,0) circle (1.0cm);
    strand [ultra thick, black] (3,0) circle (1.0cm);
end{knot}
end{tikzpicture}

end{document}

I cant't comment due to the cookie policy on this computer, so please do not ask me questions!

user30471 · Answer

Your knot has four crossings, labelled top to bottom and then left to right. Based on what you call correct and incorrect it looks like you only want to flip the third crossing.
The following code shows the effect of no flips and then flipping 1,2,3,4 in order.

This was produced using the MWE:
documentclass[tikz, border=2mm]{standalone}
usetikzlibrary{knots}

begin{document}

begin{tikzpicture}
begin{knot}[
    %draft mode=crossings ,
    clip width=3,
    flip crossing/.list={},
    ]
    strand [ultra thick, black] (0,0) circle (1.0cm);
    strand [ultra thick, black] (1.5,0) circle (1.0cm);
    strand [ultra thick, black] (3,0) circle (1.0cm);
end{knot}
   node[fill=white] at (1.5,1.5) {No flips};
end{tikzpicture}

begin{tikzpicture}
begin{knot}[
    %draft mode=crossings ,
    clip width=3,
    flip crossing/.list={1},
    ]
    strand [ultra thick, black] (0,0) circle (1.0cm);
    strand [ultra thick, black] (1.5,0) circle (1.0cm);
    strand [ultra thick, black] (3,0) circle (1.0cm);
end{knot}
   node[fill=white] at (1.5,1.5) {Flipping 1};
end{tikzpicture}

begin{tikzpicture}
begin{knot}[
    %draft mode=crossings ,
    clip width=3,
    flip crossing/.list={2},
    ]
    strand [ultra thick, black] (0,0) circle (1.0cm);
    strand [ultra thick, black] (1.5,0) circle (1.0cm);
    strand [ultra thick, black] (3,0) circle (1.0cm);
end{knot}
   node[fill=white] at (1.5,1.5) {Flipping 2};
end{tikzpicture}

begin{tikzpicture}
begin{knot}[
    %draft mode=crossings ,
    clip width=3,
    flip crossing/.list={3},
    ]
    strand [ultra thick, black] (0,0) circle (1.0cm);
    strand [ultra thick, black] (1.5,0) circle (1.0cm);
    strand [ultra thick, black] (3,0) circle (1.0cm);
end{knot}
   node[fill=white] at (1.5,1.5) {Flipping 3};
end{tikzpicture}

begin{tikzpicture}
begin{knot}[
    %draft mode=crossings ,
    clip width=3,
    flip crossing/.list={4},
    ]
    strand [ultra thick, black] (0,0) circle (1.0cm);
    strand [ultra thick, black] (1.5,0) circle (1.0cm);
    strand [ultra thick, black] (3,0) circle (1.0cm);
end{knot}
   node[fill=white] at (1.5,1.5) {Flipping 4};
end{tikzpicture}

end{document}

How does flip crossings key work?

One Answer

Add your own answers!

Ask a Question