# Coordinate System

The coordinate system in Alloverse has the following properties:

- One unit is 1 meter
- Coordinate system is right-handed. This implies…
- Negative X is left/west, positive X is right/east.
- Negative Y is down, positive Y is up.
- Negative Z is forward/north, positive Z is back/south.
- Positive rotation is counterclockwise about the axis of rotation.
- Rotations are always represented in radians.
- Y=0 is floor level in model space
- The neutral pose of all models, avatars, app UIs etc should should face towards positive Z, with “right” being positive X and “up” being positive Y.
- For textures, UV 0,0 is bottom-left, with positive U towards the right, and positive V upwards.
- The origin of an entity should be in its middle.

## Representation

Transforms are always represented using a 16-element transformation matrix. Such a 4x4 matrix is represented in data models with a column-major 16-element list of numbers.