## Fixed frame definition

@FIXED_FRAME_DEFINITION {
@FIXED_FRAME_NAME {FxdFrameName} {
@POINT1_NAME {Point1Name}
@POINT2_NAME {Point2Name}
@POINT3_NAME {Point3Name}
}
}

### Notes

1. A fixed frame is a basic geometric object that consists of an origin point, E, and of an orientation triad, E = (e1, e2, e3), as depicted in fig. 1.
2. ##### Figure 1. Definition of a fixed frame.
3. A default fixed frame called FrameName = FXDFRAME_INERTIAL is predefined and can be used without being defined explicitly. This frame coincides with the inertial frame, I = (i1, i2, i3).
4. It is possible to attach comments to the definition of the object; these comments have no effect on its definition.

### Definition of fixed frames

Fixed frames can be defined in one of the three alternative manners described below.

1. The fixed frame is defined by one point and one triad. The detailed algorithm used to obtain the fixed frame makes use of the Cartesian coordinates of point Point1Name and of orientation of triad TriadName.
2. ##### Figure 2. Definition of a frame.
3. The fixed frame is defined by two points and one triad. The detailed algorithm used to obtain the fixed frame makes use of the Cartesian coordinates of points Point1Name and Point2Name and of orientation of the third unit vector of triad TriadName.
4. The fixed frame is defined by three points. The detailed algorithm used to obtain the fixed frame makes use of the Cartesian coordinates of points Point1Name, Point2Name, and Point3Name.