Fig. 12.

Different perspectives of a CAGD solid model: a visible part of the object and its topological entities (to be precise, the related geometric objects, i.e., points, curves, and surfaces, are displayed), b the geometric segments of the B-Rep and c the underlying mathematical parameterization of each surface. In c, dashed lines mark the boundary of the visible area and gray lines indicate the underlying tensor product basis. Note that the parameterization along common edges does not match