ProCalc provides many pre-defined types that define specific ent= ities that are meaningful in the context of kinematic or kinetic analysis o= f 3D motion data. These types are used for all calculations. The following = types are defined:

**Number.**A floating-point value with or without a unit,= for example**15.6kg**.**Angle.**A single-component angle with unit in degrees o= r radians.**Voltage, Length, Time, Percentage, Frequency.**Numbers = where the units are fixed.**Point.**A specific location in 3D space, for example th= e location of a marker or a calculated joint center. Points always have a l= ength-based unit such as mm or m.**Vector.**A direction in 3D space and can be visualized = as an arrow. For example, a vector could define the direction from one poin= t to another, the direction of movement, or a velocity.**Euler Angle.**A 3D angle that describes the rotation be= tween two segments, or between a segment and the global reference frame.**Moment, Force, Power.**3D kinetic variables, either cal= culated by a biomechanical model or measured by a force plate.**Line.**A line has a location and a direction in 3D spac= e. It is defined by a point that the line passes through, and a vector that= defines its direction. A line does not have a start or end point.**Plane.**A plane is defined by a point which is containe= d in the plane as well as a vector that defines the plane's normal vector.<= /li>**Rotation.**A rotation is a 3x3 rotation matrix that des= cribes the 3D rotation from one segment to another. A rotation can be decom= posed to Euler angles.**Segment.**A segment has both a 3D location and orientat= ion in space. Its location is defined by the position of its origin, wherea= s the orientation by its rotation from the global (laboratory) coordinate s= ystem.