Or know the height of the person/object.

Before you can look at your data, you need to use the calipers to enter a measurement that is in the same plane of motion as the performance. It is easiest to hold up a meter stick at the beginning of the performance. Before starting your analysis you can use the calipers to input this measurement. Alternatively, you can also use the calipers to input the known size of a person or object. It is important that size is input correctly so that the app can make accurate calculations.