Coordinates
Coordinates are used to describe locations. Each one is a group of "ordinate" numbers which taken together can be plotted on a grid, one ordinate per dimension.
Coordinates in Source are (X,Y,Z), where X is forward/East, Y is left/North, and Z is up. (0,0,1) is a point one unit directly above the origin.
Source is using right handed coordinate system.
Coordinates are often stored alongside a set of rotation angles.
Note:'Global' or 'absolute' coordinates refer to the coordinates of the world. All other coordinate systems are 'local' to an entity.Note:In world, X axis is east and Y axis is north. In Studiomdl Data, X axis is north and Y axis is west.Note:The compass shown when the nav_show_compass console variable is toggled shows x axis is east and y axis is south. This doesn't make any sense, because in reality, turning left from north will turn to west instead of east.Origin
The origin of an object is the point at which its local coordinates are (0,0,0). It is the mathematical centre from which local coordinates are relative. It is rarely the centre of the visible object, however.
Tip:There can be multiple origins within the same entity: its own origin, the origin of its model, etc. Each origin defines its own local coordinate system relative to its parent.