This part of ISO 10303 specifies the interpretation of the integrated resources to satisfy requirements for the description of geometric shapes by means of non-manifold surface models. The following are within the scope of this part of ISO 10303: — 3D points; — points defined in the parameter space of curves or surfaces; — 3D curves; — curves defined in the parameter space of surfaces; NOTE — Such curves are also known as pcurves or cons, which are acronyms for parametrised curve and curve on surface. — the elementary curve types line, circle, ellipse, parabola, and hyperbola; — intersection curves; — polylines that consist of at least three points; — the elementary surface types plane, cylinder, cone, torus, and sphere; — swept surfaces created by rotation or linear extrusion of a curve; — sculptured curves and surfaces; — trimming of curves and surfaces using topological entities; — composition of curves and surfaces using topological entities; — replication of curves, surfaces, and surface models; — 3D offsets of curves and surfaces; — non-manifolds. The following are outside the scope of this part of ISO 10303: — unbounded geometry; — self-intersecting geometry; — geometry in a 2D cartesian coordinate space; — replication of points; — topology without an association to a corresponding geometric domain.