1. Chapter-2 Computer Aided Drafting

2. Study of AutoCAD software for the Engineering Graphics course Know the required AutoCAD commands for the course Practice the AutoCAD commands to acquire a drawing skill Learning Objectives

3. Advantages of Computer Aided Drafting 1.High speed, huge storage space and rapid recall capabilities. This results in reduction of drafting labour and drafting time. 2.We can quickly correct a drawing error and see a revised picture on the graphic screen. 3.Visual modeling of any object or engineering component is possible. 4.Once a component is drawn it can be copied and inserted at many places 5.Colour graphics help to display more distinct information on the screen, highlight certain important features, etc. 6.It can be exported to commercial analysis software for analysis purpose. 7.It is used in the creation, modification, analysis and optimization of designs for improved engineering productivity.

4. Applications of Computer Aided Drafting Mechanical : Design of machine elements, CNC machine tools, Robotics. Automotive: Kinematics, Hydraulics, Steering. Electrical: Circuit layout, Panel design, control system. Electronics: Schematic diagrams of PCs, Ics, etc. Communication: Communication network, satellite transmitting pictures, T.V. telecasting. Civil: Mapping, contour plotting, building drawing, structural design. Architectural: Town planning, interior decorations, multi storyed complex. Aerospace: Design of spacecraft, flight simulator, lofting, etc.

5. AutoCAD R-10 a drafting tool

6. Advantages of AutoCAD R-10 R10 graphic screen is broad and suitable for the basic course of engineering drawing. This graphic screen helps to accommodate number of drawings for practical assignments as well as for online examinations. AutoCAD, R10 is both command based and menu based version. Like the windows based version of AutoCAD, icons are not present in R-10. It teaches basics of 2-D and 3-D drawing and solid modeling which is easy to learn for first year students. The R10 version is now open source software and can be downloaded from internet.

7. Key points and Important Guidelines during Command Operation 1. AutoCAD does not have any unit like meter or millimeter. It has got its own unit called as AutoCAD unit. 2. Prompt means an instruction or symbol asking user to implement the next operation. 3. The input at the command prompt is case insensitive (capital letters or small letters can be input). 4. There are only two important instructions for user. These instructions are enclosed in square bracket as shown in (4) and (5). 5. [Enter] to instruct ‘Press Enter Key’ 6. [Select ……….] to instruct ‘Select Object’. The cursor is converted into a target box ‘□’ to select entity (object) in AutoCAD. 7. The parenthesis is used for user (information) during command steps. 8. Text in angle bracket e.g. gives a default option. Other options are shown separated by an oblique sign: Xyz/Pqr/Abc : In this response shown above, the lmn option is a default option. To activate other options first capital letter is required to be typed. e.g. to activate Xyz option, X needs to be typed and to activate Pqr option, P needs to be typed.

8. Use of Mouse for AutoCAD software (a) Left button (i) To select object (ii) To select location (iii) To create a window to cover an object or number of objects (b) Right button (i) Instead of Enter Key this is used, wherever [Enter] instruction is given. (ii) To cancel current command (iii) To carry forward just previous command used instead of typing the same. (c) Mouse is dragged to create a window or to displace an object from one location to another location.

9. C:\>cd acad10 C:\ACAD10> acad (Now we will reach to main menu of AutoCAD 10) 0Exit AutoCAD 1Begin a NEW drawing 2Edit an EXISTING drawing 3Plot a drawing 4Printer plot a drawing 5Configure AutoCAD 6File utilities 7Compile shape / font description file 8Convert old drawing file Enter selection: 1 Enter name of the drawing: 9A324501

10. Graphic Screen of AutoCAD R-10 Top Menu Right Menu Drawing Area Command Window TOOLSDRAWMODIFY DISPLAY SETTINGS OPTIONS FILE HELP

11. AutoCAD graphic screen

12. Practice Commands Following group of commands are required for Engineering Graphics Initial setup commands Utility commands Drawing Aids Entity DRAW commands Display commands Edit commands Note: [In the book, wherever any command is used it is shown in capital letters and command steps are shown in Times New Roman font]