Tracking topological changes in parametric models

Meiden, Hilderick A. van der; Bronsvoort, Willem F.

doi:10.1016/j.cagd.2009.12.003

Cited by 19 publications

(7 citation statements)

References 12 publications

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“…As direct modeling is a relatively new notion in the CAD domain, there has not been much research work related to GTIP detection. Existing methods [12,[40][41][42][43] consistently employ a heuristic strategy to check if a given modeling operation will cause GTIs and when they occur. The basic idea is: it first relates GTIPs to degenerated configurations of boundary faces (e.g., two originally intersected planes become parallel), and then checks if those generated degenerated configurations can actual happen.…”

Section: Next Gtip Detectionmentioning

confidence: 99%

“…In parametric modeling, there are also some research studies [41,42] related to GTIP detection. Their task is to compute critical points at which the model topology changes during parametric edits.…”

Section: Next Gtip Detectionmentioning

confidence: 99%

“…This is a little different from the problem considered here, but the notion of these critical points is conceptually similar. The methods presented in [41,42] also employ heuristics on possible degenerated face configurations to predict topology change points during a parametric modification. Nevertheless, before checking degenerated face configurations, they first identify boundary faces affected by the modeling operation to reduce checking time (to be called the culling idea).…”

Section: Next Gtip Detectionmentioning

confidence: 99%

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Variational Direct Modeling: A framework towards integration of parametric modeling and direct modeling in CAD

Zou,

Feng,

Gao

2023

Preprint

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Feature-based parametric modeling is the de facto standard in CAD. Boundary representation-based direct modeling is another CAD paradigm developed recently. They have complementary advantages and limitations, thereby offering huge potential for improvement towards an integrated CAD modeling scheme. Most existing integration methods are developed by industry and typically treat direct edits as pseudo-features, where little can be said about seamless integration. This paper presents an alternative method for seamless parametric/direct integration, which allows parametric and direct edits to work in a unified way. The fundamental issues and challenges of parametric/direct integration are first explained. A framework is then proposed to handle those information inconsistencies, based on a detection-then-resolution strategy. Algorithms that can systematically detect and resolve all possible types of information inconsistencies are also given to implement the framework. With them, model validity can be maintained during the whole model editing process, and then the discrepancy between direct edits and parametric edits can be resolved. The effectiveness of the proposed approach has been shown with a series of case studies and comparisons, based on a preliminary prototype.

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Section: Next Gtip Detectionmentioning

confidence: 99%

Section: Next Gtip Detectionmentioning

confidence: 99%

Section: Next Gtip Detectionmentioning

confidence: 99%

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Variational Direct Modeling: A framework towards integration of parametric modeling and direct modeling in CAD

Zou,

Feng,

Gao

2023

Preprint

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“…Van der Meiden and Bronsvoort (Van der Meiden and Bronsvoort, 2010) proposed a method to compute valid ranges of individual parameters in 3D parametric and feature-based modeling. The basic idea of the method is building a 3D geometric constraint system relating parameters and topology entities to construct degenerate cases where the model topology may change.…”

Section: Problem For Valid Modelsmentioning

confidence: 99%

Towards computing complete parameter ranges in parametric modeling

Tang¹,

Qiang²,

Gao³

2022

Preprint

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In parametric design, the geometric model is edited by changing relevant parameters in the parametric model, which is commonly done sequentially on multiple parameters. Without guidance on allowable parameter ranges that can guarantee the solvability of the geometric constraint system, the user could assign improper parameter values to the model's parameters, which would further lead to a failure in model updating. However, current commercial CAD systems provide little support for the proper parameter assignments. Although the existing methods can compute allowable ranges for individual parameters, they face difficulties in handling multi-parameter situations. In particular, these methods could miss some feasible parameter values and provide incomplete allowable parameter ranges. To solve this problem, an automatic approach is proposed in this paper to compute complete parameter ranges in multi-parameter editing. In the approach, a set of variable parameters are first selected to be sequentially edited by the user; before each editing operation, the one-dimensional ranges of the variable parameters are presented as guidance. To compute the one-dimensional ranges, each variable parameter is expressed as an equality-constrained function, and its one-dimensional allowable range is obtained by calculating the function range. To effectively obtain the function range which can hardly be calculated in a normal way, the function range problem is converted into a constrained optimization problem, and is then solved by Lagrange multiplier method and the Niching particle swarm optimization algorithm (the NichePSO). The effectiveness and efficiency of the proposed approach is verified by several experimental results.

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“…Authors van der Meiden et al presented a method to compute the critical values when a single parameter of a model is modified, (i.e. the parameter values for which the topology of the model changes) [136]. Accordingly, MQT tools could simply highlight those parameters that are particularly sensitive to changes, making explicit where a model is robust but barely flexible.…”

Section: Semantic Errors In Procedural Cad Modelsmentioning

confidence: 99%