# Coordinates

From Valve Developer Community

(Redirected from PlacementOrigin)

**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.

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 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.