This command will set the laboratory coordinate system

Set_Laboratory_Coordinate_System /AP_DIRECTION=Y /AXIAL_DIRECTION=Z ; The user is allowed only to select two of the principal axes of the laboratory coordinate system because Visual3D only permits a right handed coordinate system.

Setting the Laboratory Coordinate System (LCS) in Visual3D has many consequences. First, the LCS defines the coordinate system in which the Motion Capture data was recorded. Second, the LCS defines the direction of gravity. Third, the LCS defines the default Segment Coordinate System when a segment is created in Model Builder.