function arcPoint
entryArc.ts:150
A point of the conic, as a displacement from the center.
psi from apoapsis; radius overrides the conic's own — the radial case
has no other way to say where along the line it is, and a descent that has
clamped its height above a mountain wants the direction of the conic at the
radius it is actually at.
- arcEntryArc
- Undocumented
- psinumber
- Undocumented
- radiusnumber
- Undocumented
ReturnsVec3