Micro Geometry Flaws in the Exchange of Design Data Using STEP

A fundamental issue in concurrent engineering is sharing data among a vanety of commercially available computer-aided de sign, analysis, and manufacturing software tools. Geometry flaws often occur in the exchange of design data between dissimilar CAD systems and have multiplied with the ever-increasing complexity of product geometry. in recent years the international standard ISO 10303, STEP (Standard for the Exchange of Product model data), has achieved a success rate of 95-98% in the exchange of design data. This paper demonstrates that a significant portion of these errors are the result of the different degrees of precision used by com mercial CAD systems and are often apparent as minute gaps ranging from 0.00001-0.1 mm. The consequences are micro geometry gaps that are not visible to the designer but influence the creation of the final geometry at the receiver's end. Research has found that these gaps can be directly linked to the incompatibility in the degrees of precision used by individual CAD systems to associate vertices and curves with related faces.