Object Recreation from Facet Representation to IGES and Primitive Representations

Accurate geometric and mathematical modeling of three-dimensional object shapes is a critical component of a variety of applications, ranging from design and manufacturing, to modeling and simulation. The models used in these applications may be created using interactive Computer Aided Design (CAD) tools, by hand-editing geometry configuration files, as the outputs of automated systems such as laser ranging scanners, computer-vision-based shape-from-motion techniques, or optimized design codes. While some model formats allow higher-level representations, combining geometric primitives or bounded surfaces to represent the final 3D shape, many model sources or existing model collections contain only lower-level representations such as a facets or meshes. While conversion from higher-level to lower-level representations is common using facetization or meshing techniques, this research effort focuses on the inverse problem of generating higher-order shape representations from faceted models. This requires recognizing groups of facets that collectively represent higher-order surfaces such as cylinders, spheres, cones, and lofted curved surfaces; mathematically fitting surface equations to those facets to determine the characteristic shape parameters; and exporting the high-order representations to formats that modeling, simulation, and analysis tools can process. These techniques will enable smooth surface CAD models to be created automatically from roughly triangulated input geometries.