# Units and Coordinates in HoloOcean

HoloOcean uses **meters** for units and a **right-handed coordinate system** for
all locations, distances, and offsets.

## Coordinate System

Unreal Engine uses a left handed coordinate system by default, however
to keep with general robotics conventions, we use a right handed coordinate
system with positive `z`

being up.

So, when you need to specify a location in HoloOcean, the format is as follows

`[x, y, z]`

where:

Positive

`x`

is**forward**Positive

`y`

is**left**Positive

`z`

is**up**

Remember that the units for `[x, y, z]`

are in meters (Unreal Engine
defaults to centimeters, we’ve changed this to make things a bit easier).

## Rotations

Rotations are specified in `[roll, pitch, yaw]`

/ `[x, y, z]`

format, in in degrees (usually). This means

**Roll**: Rotation around the fixed forward (`x`

) axis**Pitch**: Rotation around the fixed right (`y`

) axis**Yaw**: Rotation around the fixed up (`z`

) axis

In that order.