Annotation Mechanisms to Manage Design Knowledge in Complex Parametric Models and Their Effects on Alteration and Reusability

Abstract

ACKNOWLEDGEMENTSI would like to express my deepest gratitude and appreciation to my advisor, Professor Dr. Manuel Contero, for his expert guidance, support, and valuable suggestions and critiques to this work. Thank you for accepting me as your PhD student and giving me the opportunity to work with you. I honestly could not have asked for a better advisor.I also thank my family for their love, patience, and support throughout this process and for letting me steal their valuable time to work on this dissertation. It is my hope that their sacrifice has finally paid off. ABSTRACTDespite the evolution of technologies intended to facilitate and optimize product development processes and foster collaboration, effective reuse of 3D models remains one of the biggest challenges in the area of ComputerAided Design. Whether a manufacturer is designing a new commercial aircraft or a household appliance, engineering teams often start with existing designs and adapt them to new cases, rather than designing every product from scratch. Nevertheless, CAD model reuse is not effectively supported by conventional CAD packages, as much of the burden related to reusability lies on the CAD user.It has been shown that CAD model reusability largely depends on a proper definition and communication of the geometric design intent, which are usually expressed implicitly within the CAD model. This implicit representation makes it difficult for CAD users interacting with a CAD model to understand how and why the model was created in a specific manner. This is especially true for models being reworked by designers that are not the original creators of the models. The inability to understand and modify existing CAD models negatively affects reusability and hinders the collaborative design process. The problem becomes more relevant in modelbased engineering environments, where 3D models are used as the main shared data source for all engineering activities throughout the product life cycle.Recent research has explored the potential of 3D annotations as tools to carry design intent information. The focus of this doctoral research is to study the effectiveness of 3D CAD annotation techniques to support the explicit representation and communication of design intent, and to analyze the impact of these techniques in the alteration and reutilization of 3D models in a product design context. Literature shows that a good and structured methodology is an essential step to create parametric models that are reusable and can be altered easily. However, when models reach a certain level of complexity in terms of number of features and interdependencies, additional mechanisms must be established so design intent can be communicated effectively in an explicit manner. In this regard, a comparative study was conducted to determine the complexity of three professionally accepted modeling methodologies. These methodologies represent a group of well tested and documented methodologies that are currently available to the public. An efficient 5 modeling methodology c...