A Study on Extending Boundary-Representation for Robust Blending (1st report)

Abstract

A solid model representing a product requires filleting or blending, which rounds a specified edge or vertex, in order to make a production model for manufacturing purpose such as mould die model. Many research algorithms for blending have been proposed and commercial CAD/CAM system vendors have implemented blend functions for their systems, however, the practicing users of CAD/CAM systems in the manufacturing industry are suffering from the inability of current blending functions, such as some “holes” in the solid models because of the failure of the blending. We regard that the current major solid model structure, the Boundary-Representation (B-rep) lacks the sufficient structure for making robust blending surfaces. In our research, we propose several additional conditions for the B-rep that includes “extended surfaces” that make the blending algorithm simple and robust. In this report, we show that our proposed conditions are effective in the case of three-edge vertex blending. Several examples are shown to verify the effectiveness of our proposal.