Feature-Based Design Using NURBS Entities and Plex Grammar

Author(s):  
Xiaogang Guan ◽  
Vassilios E. Theodoracatos

Abstract A new feature-based design synthesis methodology is described. Features of various levels of complexity are created and classified according to their attributes. Each feature is represented as a single internal NURBS surface. A hierarchical structure of features with corresponding parameters is maintained to enhance the design efficiency. Plex grammar is used as a structure relationship descriptor to facilitate product concept analysis and geometric synthesis. Two product design examples are presented to illustrate the concept analysis and geometric synthesis process.

Author(s):  
S. N. Trika ◽  
P. Banerjee ◽  
R. L. Kashyap

Abstract A virtual reality (VR) interface to a feature-based computer-aided design (CAD) system promises to provide a simple interface to a designer of mechanical parts, because it allows intuitive specification of design features such as holes, slots, and protrusions in three-dimensions. Given the current state of a part design, the designer is free to navigate around the part and in part cavities to specify the next feature. This method of feature specification also provides directives to the process-planner regarding the order in which the features may be manufactured. In iterative feature-based design, the existing part cavities represent constraints as to where the designer is allowed to navigate and place the new feature. The CAD system must be able to recognize the part cavities and enforce these constraints. Furthermore, the CAD system must be able to update its knowledge of part cavities when the new feature is added. In this paper, (i) we show how the CAD system can enforce the aforementioned constraints by exploiting the knowledge of part cavities and their adjacencies, and (ii) present efficient methods for updates of the set of part cavities when the designer adds a new feature.


1997 ◽  
Vol 32 (2) ◽  
pp. 383-397 ◽  
Author(s):  
Der-Baau Perng ◽  
Chao-Fan Chang

2020 ◽  
Vol 124 (1281) ◽  
pp. 1761-1788
Author(s):  
L. Rana ◽  
B. Chudoba

ABSTRACTThe early conceptual design (CD) phase of space access vehicles (SAVs) is the most abstract, innovative and technologically challenging phase of the entire aerospace design life cycle. Although the design decision-making during this phase influences around 80 percent of the overall life cycle cost, it is the most abstract and thus least understood phase of the entire design life cycle. The history of SAV design provides numerous examples of project failures that could have been avoided if the decision-maker had had the capability to forecast the potential risks and threats correctly ahead of time during the conceptual design phase. The present study addresses this crucial phase and demonstrates a best-practice synthesis methodology prototype to advance the current state of the art of CD as applied to SAV design. Developed by the Aerospace Vehicle Design (AVD) Laboratory at the University of Texas at Arlington (UTA), the Aerospace Vehicle Design Synthesis process and software (AVDS) is a prototype solution for a flight vehicle configuration–flexible (generic) design synthesis capability that can be applied to the primary categories of SAVs. This study focusses on introducing AVDS, followed by the demonstration and verification of the system’s capability through a sizing case study based on the data-rich Boeing X-20 Dyna-Soar spaceplane.


2007 ◽  
Vol 4 (1-4) ◽  
pp. 497-507
Author(s):  
Jason H. Elliott ◽  
Courtney L Berglund ◽  
C. Greg Jensen

1993 ◽  
Vol 5 (3-4) ◽  
pp. 218-237 ◽  
Author(s):  
Jami J. Shah ◽  
Mary T. Rogers

Author(s):  
David W. Rosen

Abstract Features are meaningful abstractions of geometry that engineers use to reason about components, products, and processes. For design activity, features are design primitives, serve as the basis for product representations, and can incorporate information relevant to life-cycle activities such as manufacturing. Research on feature-based design has matured to the point that results are being incorporated into commercial CAD systems. The intent here is to classify feature-based design literature to provide a solid historical basis for present research and to identify promising research directions that will affect computer-based design tools within the next few years. Applications of feature-based design and technologies of feature representations are reviewed. Open research issues are identified and put in the context of past and current work. Four hypotheses are proposed as challenges for future research: two on the existence of fundamental sub-feature elements and relationships for features, one that presents a new definition of design features, and one that argues for the successful development of concurrent engineering languages. Evidence for these hypotheses is provided from recent research results and from speculation about the future of feature-based design.


Author(s):  
Maarten J. G. M. van Emmerik

Abstract Feature modeling enables the specification of a model with standardized high-level shape aspects that have a functional meaning for design or manufacturing. In this paper an interactive graphical approach to feature-based modeling is presented. The user can represent features as new CSG primitives, specified as a Boolean combination of halfspaces. Constraints between halfspaces specify the geometric characteristics of a feature and control feature validity. Once a new feature is defined and stored in a library, it can be used in other objects and positioned, oriented and dimensioned by direct manipulation with a graphics cursor. Constraints between features prevent feature interference and specify spatial relations between features.


Sign in / Sign up

Export Citation Format

Share Document