3.3 Principal reference planes and anthropometric planes

Three principal reference planes are defined from the axes of the Model Reference System, as shown in Figure 3. These planes are associated with the model's orientation and do not remain fixed relative to the scene.

• The XY plane contains the X and Y axes of the Model Reference System. This plane is horizontal in the model's initial position and coincides with the transverse anthropometric plane. Its positive normal vector is aligned with the Z axis of the Model Reference System and points upward.

• The XZ plane contains the X and Z axes of the Model Reference System. In the initial position, it is vertical and coincides with the frontal anthropometric plane. Its positive normal vector is aligned with the Y axis and points toward the front of the model.

• The YZ plane contains the Y and Z axes. In the initial position, it is vertical and coincides with the sagittal anthropometric plane. Its positive normal vector is aligned with the X axis and points toward the model's right.

These elements can be displayed using the Reference system, Sagittal plane, Frontal plane, and Transverse plane controls in the Visualization menu on the right side of the interface.