Computer-aided Design Workstation Research Articles

Visual discomfort among university students who use CAD workstations

Extensive literature in ergonomics and optometry has indicated that computer use is closely associated with visual problems. Computer-Aided Design (CAD) requires a substantial effort on behalf of the visual system. The manifestations of visual fatigue phenomena may affect the working behavior and the human-system interaction. The aim of this survey is to identify the normal working conditions and how the eventual visual fatigue phenomena are able to influence the working behavior of CAD users. A questionnaire was created and submitted to a sample of 150 university students, who attend the Faculty of Engineering of the University of Pisa (Italy). The questionnaire results show that university students spend on average 7 hours per day at the computer for CAD drafting. Most of the participants work in strongly lit environments, with high brightness screens and negative polarity. Such conditions cause high contrasts in luminance, especially between screen and surfaces that fall within the field of vision. The results show that 135 out of 150 students report visual fatigue during long CAD sessions, which in most cases leads to difficulty in continuing the activity and changing usual working behavior. The results of the questionnaire show that the university students work in highly variable lighting conditions and with little attention on the luminance distribution on the field of view. This has highlighted the importance, for VDT workstations, of not limiting the risk analysis to the postural ergonomics (how usually occurs) but extend it to the workplace as a whole, analyzing also the ergonomics of vision, which involves different consideration on the natural and artificial lighting of the workplace and on the characteristics of the display.

The development of a three dimensional imaging system and its application in computer aided design workstations

This paper details the application of a three dimensional imaging system known as planar contour imaging (PCI) to the presentation of images created by computer aided design (CAD) software. The three dimensional computational models were generated within a commercially available CAD/CAM software package from Delcam plc and then converted to stereo lithographic (.stl) format. The .stl file was then converted into a real, three dimensional, image by PCI. It was found that, in the same way that a user looks at a two dimensional image, the selection of the correct type and amount of data presented to the viewer was critical. However, when the image was refined, the three dimensional image was found to produce an impressive representation of the computational dataset.

Computer aided design of computer generated holograms for electron beam fabrication

Computer Aided Design (CAD) systems that have been developed for electrical and mechanical design tasks are also effective tools for the process of designing Computer Generated Holograms (CGHs), particularly when these holograms are to be fabricated using electron beam lithography. CAD workstations provide efficient and convenient means of computing, storing, displaying, and preparing for fabrication many of the features that are common to CGH designs. Experience gained in the process of designing CGHs with various types of encoding methods is presented. Suggestions are made so that future workstations may further accommodate the CGH design process.

CAD in the CIM Environment: Where Do We Go From Here?

The importance of computer-aided design (CAD) has not been fully appreciated as it relates to computer integrated manufacturing (CIM). The CAD product definition model can provide essential information for many down-stream production, estimating, tooling, and quality assurance functions in the CIM environment. However, the product definition model may be inaccurate or incomplete, thus causing incomplete communication with possible scrap, re-work, and missed production deadlines. Other problems are related to the fact that many of our expert designers are retiring and taking their expertise with them. Merely being able to make 2D or 3D drawings on a CAD workstation does not make its operator a designer. A knowledge of production processes, tolerances, surface finish, and material selection is needed to supplement a designers knowledge of user needs, product functional requirements, operating conditions, cost, quality, and reliability targets. One of the most promising methods for providing timely and accurate information to the designer on an “as-needed” basis is through the use of expert design systems. Such systems promise to bridge the knowledge gap between CAD and CAM and help to incorporate these functions into the overall CIM environment.

Turning your PC into a CAD workstation

Computer-aided design (CAD) packages are now available on some personal computers, and can make a good entry system for design offices. However, it is important to take into account the additional costs that might be incurred e.g. more memory, a graphics monitor, a lightpen etc.