tailieunhanh - Mechanisms and Mechanical Devices Sourcebook Episode 2 Part 5

Tham khảo tài liệu 'mechanisms and mechanical devices sourcebook episode 2 part 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | _CHAPTER 14 NEW directions in MACHINE Design SOFTWARE IMPROVEMENTS EXPAND CAD CAPABILITIES Computer Aided Design CAD is a computer-based technology that allows a designer to draw and label the engineering details of a product or project electronically on a computer screen while relegating drawing reproduction to a printer or X-Y plotter. It also permits designers in different locations to collaborate in the design process via a computer network and permits the drawing to be stored digitally in computer memory for ready reference. CAD has done for engineering graphics what the word processor did for writing. The introduction of CAD in the late 1960s changed the traditional method of drafting forever by relieving the designer of the tedious and time-consuming tasks of manual drawing from scratch inking and dimensioning on a conventional drawing board. While CAD offers many benefits to designers or engineers never before possible it does not relieve them of the requirement for extensive technical training and wide background knowledge of drawing standards and practice if professional work is to be accomplished. Moreover in making the transition from the drawing board to the CAD workstation the designer must spend the time and make the effort to master the complexities of the specific CAD software systems in use particularly how to make the most effective use of the icons that appear on the screen. The discovery of the principles of 3D isometric and perspective drawing in the Middle Ages resulted in a more realistic and accurate portrayal of objects than 2D drawings and they conveyed at a glance more information about that object but making a 3D drawing manually was then and is still more difficult and time-consuming calling for a higher level of drawing skill. Another transition is required for the designer moving up from 2D to 3D drawing contouring and shading. The D in CAD stands for design but CAD in its present state is still essentially .