Difference between XYZPoint and XYZVector

What is the difference between an XYZPoint object and an XYZVector object?

Welcome to the ROOT Forum!
According to the Point 3D Page and the Vector 3D Page:
ROOT::Math::XYZPoint point based on x,y,z coordinates (cartesian) in double precision
ROOT::Math::XYZVector vector based on x,y,z coordinates (cartesian) in double precision

Hi, I have looked at those pages, but I don’t understand what the difference is (if any). I just see they both have the same members and functions.

Thanks

The ROOT::Math::XYZPoint is a position and ROOT::Math::XYZVector a displacement. Maybe @emoneta can give more details…

For example, you can add two DisplacementVectors, but you cannot add two PositionVectors, as it does not make sense to ‘add’ two points.

Also, I think that, if you have two coordinate systems, one translated from each other, the PositionVector of a point P is different in each coordinate system, but a DisplacementVector would be exactly the same.