How to rotate a plotted igraph, given a specific layout (r code)?

Question

I have the following code:

require(igraph)
g = make_star(8, mode="undirected", center=1)
layout.old = layout_with_fr(g, dim=3)
plot(g, layout = layout.old)

I'd like to plot the same graph but with a rotation of degree a for any a wrt the original layout, wrt a fixed axis, no matter what it is. The idea is to construct a step-wise animation, so I need to plot a new graph (using the function 'plot') for each step (each step gives the same graph, but rotated).

How to do that?

Thanks so much in advance!

Answer 1

You can do it using the rgl::rotate3d function. For example to rotate by 10, 20, ..., 100 degrees about the axis in direction (x,y,z) = (1,1,1) use

for (a in 10*(1:10)) {
   plot(g, layout = rgl::rotate3d(layout.old, a*pi/180, x=1,y=1,z=1))
   Sys.sleep(1)
}
  

You could also use rglplot(g, layout = layout.old) for an interactive plot.