All 3D models will have three measurements to them: height, width, and depth. These correspond to the Z, X, and Y axes.
These axes indicate both the measurement of the model and the direction in which it may move in 3D space. For example a model can be 15mm wide, and also move 15mm along the X axis.
3D modeling software can use many different units of measurement, but it is suggested to work in millimeters (mm) when possible.
