pub fn revolution(
axes: &CoordinateSystem,
from: f64,
to: f64,
) -> GeopResult<Path>Expand description
The path around the axis axes.w() through axes.origin(), from the
angle from to to — either way round — in degrees, angles turning
from axes.u() towards axes.v(): a profile point (r, z) at angle a
lies at origin + r (cos a u + sin a v) + z w.
Its stations are a0 (at from), a1, … and the spans between them
q0, q1, …, each at most a quarter turn, all equal. A full turn —
to a whole turn from from, either way — closes on itself, and always
runs backwards: q3 from a0 back to a3, then q2, q1, q0, so
that a1 lies a quarter turn on from a0.