GENERATION OF GEOMETRIC REPRESENTATIONS OF 3D OBJECTS IN CAD-CAM BY DIGITAL PHOTOGRAMMETRY

This paper presents a method for the generation of geometric represent ations of 3D objects by digital photogrammetry. In CAD/CAM systems geo metric modelers are usually used to create three-dimensional (3D) geom etric representations for design and manufacturing purposes. However, in cases where geometric information such as dimensions and shapes of objects are not available, measurements of physically existing objects become necessary. In this paper, geometric parameters of primitives o f 3D geometric representations such as Boundary Representation (B-rep) , Constructive Solid Geometry (CSG), and digital surface models are de termined by digital image matching techniques. An algorithm for recons truction of surfaces with discontinuities is developed. Interfaces bet ween digital photogrammetric data and these geometric representations are realized. This method can be applied to design and manufacturing i n mechanical engineering, automobile industry, robot technology, spati al information systems and others.