I’m trying to compute the terminator line, or at least a series of GeodeticPoints that make up the terminator, and I thought maybe the CircularFieldOfView attached to the sun and then calling the getFootprint method as it points to the Earth might work for this. That said, I’m struggling to understand the frame / transform requirements for this process. Are there any examples of how I would place a CircularFOV on the sun, and then produce a Footprint on the Earth?
I think a circular field of view detector might become very unhappy doing that depending upon how it is implemented (I don’t know myself).
Why not find the Sun → Earth vector and use it to create a plane, generate a set of vectors on that plane, and then calculate their interaction with the geoid? Using the getIntersectionPoint method of BodyShape-derived classes? It would make the assumption that the incoming rays are parallel which may not be good enough for your application.