In engineering applications such as interactive design and simulation, some of the main object manipulations include feature interaction. Today's cad systems provide object-oriented structures which can explicitly...
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In engineering applications such as interactive design and simulation, some of the main object manipulations include feature interaction. Today's cad systems provide object-oriented structures which can explicitly represent functional and geometrical interactions among features. However, conventional interaction algorithms for manipulating these structures cannot cope with non-geometrical information such as feature functionality. Interaction among features plays an essential role in defining functionality. In this paper, a new method is described which focuses on implementation of an interaction mechanism for design and simulation. Two interaction categories are handled: (1) neighboring interaction, which is primarily geometrical (blending and trimming) and (2) functional interaction (machining). Since most interactions are performed in a sub-domain rather than in the entire domain, the advantage of the locality property is considered in both cases.
A new system has been developed for improving user interaction with cad systems, particularly in the conceptual design stage. The system is based on interactive, part-by-part formation of a geometrical model using fre...
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A new system has been developed for improving user interaction with cad systems, particularly in the conceptual design stage. The system is based on interactive, part-by-part formation of a geometrical model using freehand sketching. A single 2D inaccurate projection is entered in the form of a line drawing. The system analyzes and interprets the input and then reconstructs a 3D model of the object most likely to be represented by the sketch. This 3D model can be further manipulated or modified, and more parts can be sketched. This approach provides a fluent and intuitive tool for conceptual design. In the paper, the proposed system is presented and the basic ideas are discussed and exemplified.
In this paper, a unified method for smoothing free-form surfaces with Bezier patches is presented. A non-smooth surface consisting of bicubic patches is turned into a G(1) surface by the following process. Trim each p...
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In this paper, a unified method for smoothing free-form surfaces with Bezier patches is presented. A non-smooth surface consisting of bicubic patches is turned into a G(1) surface by the following process. Trim each patch along user-defined parameter lines using subdivision. Attach eight patches (one to each edge and one to each vertex) to each trimmed patch to blend between it and its neighbor patches. Using this method, solid objects bounded with bicubic Bezier patches can be G(1) smoothed with bicubic patches. The operation is local. It provides designers with the facility to adjust the shape of a smoothed object interactively. The method can also be used for constructing smooth closed surfaces whose modeling is important for cad/CG (cf. (Barnhill, 1985)).
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