FIXED REFERENCE SWEPT SURFACE
Definition
An object is a <FIXED REFERENCE SWEPT SURFACE> if and only if: it is a <SWEPT SURFACE>; the generatrix is linked to a sweep reference point on the directrix, so that as this point is moved along the directrix, the replica of the generatrix curve has a constant relationship with: the tangent to the directrix; a normal the directrix defined by a reference direction. as defined in ISO 15926 Part 3 Section 4.6.3.25