Create a QRay3D class

QtGraphs just added API (doRayPicking(QVector3D origin, QVector3D direction)) representing a ray in 3D space without first writing a geometric class for it. There's a QRay(3D?) in Qt3D, it also does other things. A general QRay3D would make sense at the same level as QVector3D. Note: these are C++ types, not QML ones.

As a physicist, I'm also concerned about the conflation of a position vector and a direction vector (like the difference between a time point and a duration), so I wouldn't mind a QRay3D to be a (QPoint3D, QVector3D).