Tham khảo tài liệu 'manufacturing design, production, automation, and integration part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 4 Computer-Aided Design Geometric modeling is the first step in the computer-aided engineering CAE analysis of a designed product. The objective is to encapsulate all geometric data pertaining to the part in a single model and specify all necessary material properties as additional information. In this context solid modeling as a branch of geometric modeling refers to the geometric description of solid objects in their entirety. Solid models 1 must be complete the graphical model must not be an ambiguous representation 2 must have integrity operation on geometric models must preserve integrity such as maintaining the connection of edges at a point when it is moved and 3 provide accuracy in modeling of complex shapes. Solid modeling is a multifaceted operation. At the forefront a user describes a geometric model through a graphical representation to the computer which in turn stores this representation in one format or another and furthermore allows the manipulation of this representation through a set of mathematical transformations operators etc. Thus a user of a computer-aided design CAD system for solid modeling purposes should have a basic knowledge of computer graphics principles needed for the manipulation and storage of graphical data. As a preamble to solid modeling this chapter will first review geometric modeling principles and concepts in Sec. 2 and then address the Copyright 2003 by Marcel Dekker Inc. All Rights Reserved. topics of solid modeling techniques feature-based design and product-data exchange standards in Sec. 3 to 5. GEOMETRIC MODELING-HISTORICAL DEVELOPMENT Sketchpad is known as the first graphical user interface GUI developed at . by I. E. Sutherland capable of interpreting information sketched on a computer display monitor. The software was developed during the period 1960 to 1962 on a TX-2 computer and primarily utilized a light pen in conjunction with a push button for data input points straight lines circles etc. . It is .
