This part of ISO 10303 specifies the interpretation of the generic resources in order to satisfy the following requirements: — for the description of a three dimensional shape by means of a boundary representation model with planar faces and implicit straight line edges; — for the composition of one or more such shapes as a faceted_brep_shape_representation. The following are within the scope of this part of ISO 10303: — 3D geometry; — B-reps; — B-rep models; — faceted B-reps; — polyloops; — unbounded geometry; — use of topology to bound geometric entities; — geometric transformations. The following are outside the scope of this part of ISO 10303: — 2D geometry; — curves; — explicit edge definitions; — surfaces other than planes; — offset curves and surfaces.