Identifying, Correcting, and Avoiding Errors in Computer-Aided Design Models Which Affect Interoperability

Abstract

Interoperability characterizes the ability of computer-aided design (CAD) models to accurately represent objects in concurrent engineering environments. The diagnostic set of available software for interoperability testing is described. This set is utilized to develop a visual catalog of possible interoperability errors. The value of utilizing interoperability testing software is appraised by way of a real-world case study. Numerous significant errors are identified in a suite of 140 parts. “Geometry errors” are shown to be more common than “topology errors.” The case study suggests that sensitizing the designer to the nature of typical errors leads to improvement in initial model quality. Example errors are described to illustrate their nature and how to eliminate them. Informal guidelines to improve quality upon initial design are deduced. The development of errors due to inconsistent system accuracy settings during data exchange is explored.

Repairing CAD model errors based on the design history

“…Gu et al [4] sequentially sorted topological entities by using a complementary model object tree, and they used the tree to correct topological errors.…”

“…Previous studies on poor-quality CAD models have focused on the boundary representation (B-Rep) of 3-D shapes [3][4][5][6][7][8] However, although the B-Rep approach is effective for locating errors with the maximum or minimum tolerance as defined by the designer, an unstable topological structure can unintentionally distort a repaired B-Rep shape or cause the shape to collapse. As a result, only limited types of errors can be corrected, and automation of the correction process is difficult.…”

Methodology for automatic recovering of 3D partitions from unstitched faces of non-manifold CAD models

“…Most problems in data exchange are due to both the differences between internal mathematical representation schemes and to the internal accuracies of the modelling kernels integrated in the CAD systems [2,23,24]. Data exchange problems can also arise from an inadequate geometric modelling of the original model.…”

“…Deduced from experience, Gu et al [23] classify typical interoperability errors and provide a few guidelines for improving interoperability at the initial design stage. The question that arises here is how to handle 3D models of real structures already designed, for example, if we want to assess the lifecycle of the machinery or to improve its behaviour during the exploitation?…”

A Contribution to Conveying Quality Criteria in Mechanical CAD Models and Assemblies through Rubrics and Comprehensive Design Intent Quantification

“…The concept of quality in the realm of MCAD is a relatively recent topic of interest [Contero et al, 2002], [Gu et al, 2001], and [Yang et al, 2006]. Its more developed aspect relates to the geometrical and topological correctness of models, that can be evaluated with ad hoc software (quality checkers) that implement quality criteria as defined in standards such as VDA 4955 [1999] or SASIG PQD 2.1 [2005].…”