# Tracking Bar Coordinate System {% hint style="warning" %} The OptiTrack Duo/Trio tracking bars are factory calibrated and there is **no need to calibrate the cameras** to use the system. By default, the tracking volume is set at the center origin of the cameras and the axis are oriented so that Z-axis is forward, Y-axis is up, X-axis is left {% endhint %} ## Tracking Bar Coordinate System If you wish to change the location and orientation of the global axis, you can use the **Coordinate Systems Tool** which can be found under the Tools tab.

## Coordinate Systems Tool When using the Duo/Trio tracking bars, you can set the coordinate origin at desired location and orientation using a [calibration square](https://docs.optitrack.com/v2.3/motive/calibration/calibration-squares). Make sure the calibration square is oriented properly. **Adjusting the Coordinate System Steps** 1. First set place the calibration square at the desired origin. 2. **\[Motive]** Open the Coordinate System Tools pane under the Tools tab. 3. **\[Motive]** Select the Calibration square markers from the [Perspective View pane](https://docs.optitrack.com/v2.3/motive-ui-panes/viewport#perspective-view) 4. **\[Motive]** Click the **Set Ground Plane** button from the Coordinate System Tools pane, and the global origin will be adjusted.