The point hit in render space (millimetres, globalBaseTranslation included), the frame SectionPlanes.startPlaneAt and MovablePlanes.addPlane take. Null when nothing was hit
The unit normal of the surface at the coordinate, facing the camera. Null when no surface was hit
The object hit, null over empty space, the reference grid or a check overlay item
What is under a position on the canvas, from Viewer3d.pick or the third argument of the
rightMouseClicksetting. The vectors are copies, they stay valid after later picks.