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  1. EC202-Computer Aided Design PRACTICAL EVALUATION FORM NAME:………………………………………………………. CLASS.: ……………… REGISTRATION…
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  • 1. EC202-Computer Aided Design PRACTICAL EVALUATION FORM NAME:………………………………………………………. CLASS.: ……………… REGISTRATION NO.: ……………………………………… PRACTICAL WORK: 2 INTRODUCTION TO AUTOCAD WINDOWS: DATA INPUT TECHNIQUES No. Skill i. Accuracy ii. Within time frame Excellent (8-10 marks) amy/khk/jke/puo EC2.1 Average (5-7 Marks) Weak (0-4 Marks) Total 1. Create New file- Metric measurement & able to display grid 2. Absolute Coordinate Method 3. Relative Coordinate Method 4. Polar Coordinate Method Sub-Total /40 No. Report Total 1. Result: Table 2.1 /10 2. Discussion /4 3. Question /4 2. Reflection /2 Sub-Total /20 Total /60
  • 2. EC202-Computer Aided Design PRACTICAL WORK: 2 TITLE : INTRODUCTION TO AUTOCAD FOR WINDOWS COURSE LEARNING OUTCOME: CLO3: Key-in data and commands using various data input techniques to produce standard drawing. OBJECTIVES: The students should be able to: 1. Key-in data entries by using: a. Absolute Coordinate system technique. b. Relative Coordinate system technique. c. Polar Coordinate system technique 2. Compare the techniques of data inputs. THEORY : Designs and drawings created in a CAD system are usually defined and stored using sets of points in what is called world space. In most CAD systems, the world space is defined using a three-dimensional Cartesian coordinate system, usually referred to as the X, Y, and Z-axes. The intersection of the three coordinate axes forms a point called the origin, a fixed point being used as a reference for all measurements. The icon near the bottom left corner of the graphics window shows the positive X-direction and positive Y-direction of the coordinate system that is active. In AutoCAD, the coordinate system that is used to create entities is called the User Coordinate System (UCS). By default, the UCS is aligned to the world coordinate system (WCS). In AutoCAD, there are various methods to specify the locations of points: i. Random point or interactive technique ii. Absolute coordinates system iii. Relative coordinates system iv. Polar coordinates system v. Direct distance entry technique amy/khk/jke/puo EC2.2
  • 3. EC202-Computer Aided Design EQUIPMENT : 1. Desktop Computer/Laptop 2. AutoCAD 2004 Software PROCEDURE : PART A: Start The AutoCAD Program 1. Create a New drawing file and set the drawing measurement to Metric. 2. Display the grid to the extent of the drawing limits. PART B: DATA INPUTS 1. We will make use of the DRAW command <line> to start our drawing and then followed by the Data Entries techniques.  Select the Line command from either one of the following methods: i. The Pull-Down Menu <DRAW> Fig. 2.1: Pull-down menu selection <DRAW> Line ii. The Toolbar Draw Fig. 2.2: Draw Toolbar icon <Line> iii. Typing Line or L at the Keyboard Fig. 2.3: Keyboard Entry amy/khk/jke/puo EC2.3
  • 4. EC202-Computer Aided Design  Observe the message displayed at the Command prompt and AutoCAD expects us to identify the starting location (first point) of a straight line. 2. To begin a drawing, we will start with a simple example such as a rectangle ABCD as at Fig. 2.4. In this example , we will choose the origin of the world coordinate system (WCS) i.e. X,Y = 0,0 as our starting first point. D A Fig. 2.4: A Rectangle ABCD at the UCS origin 0,0 i. Technique 1: Absolute Coordinate System To locate the next point, type the X-value, Y value (DO NOT add spaces). Follow the instruction below to draw Fig 2.4: Command: Line [Enter] Step 1: To locate the starting point A: Specify first point: 0,0 [Enter] - To locate the starting point A Step 2: To locate point B: Specify next point or [Close/Undo]: 100,0 [Enter] Step 3: To locate point C: Specify next point or [Close/Undo]: 100,50 [Enter] Step 4: To locate point D: Specify next point or [Close/Undo]: 0,50 [Enter] Step 5: To locate point A again or to close the object (rectangle): amy/khk/jke/puo EC2.4 50 100 Y -X (0,0) X -Y C B
  • 5. EC202-Computer Aided Design Specify next point or [Close/Undo]: C [Enter] OR Specify next point or [Close/Undo]: 0,0 [Enter] If a mistake is made, use the undo icon, or press U or press CTRL+Z. You can also use the ERASE command to get rid of lines you don't want. ii. Technique 2: Relative Coordinate System This technique allows you to enter points in relation to the first point you have entered. To locate the next point, type @deflection of X axis , deflection of Y axis (DO NOT add spaces). Follow the instructions below to draw Fig. 2.4: Command: Line [Enter] Step 1: Specify first point: 0,0 [Enter] Step 2: Specify next point or [Close/Undo]: @100, 0 [Enter] Step 3: Specify next point or [Close/Undo]: @0,50 [Enter] Step 4: Specify next point or [Close/Undo]: @-100,0 [Enter] Step 5: Specify next point or [Close/Undo]: C [Enter] OR Specify next point or [Close/Undo]: @0,-50 [Enter] The alphabet @ means that AutoCAD will draw a line from the first point to another point X unit over Y units up relative to the previous point. iii. Technique 3: Polar Coordinate System Polar Coordinates allow you to select a point that is a specific length an at a specific angle to the last point indicated. To locate a point, type @distance<angle (DO NOT add spaces). Follow the instructions below to draw Fig. 2.4: Step 1: Command: Line [Enter] Specify first point: 0,0 [Enter] Step 2: Specify next point or [Close/Undo]: @100<0 [Enter] Step 3: Specify next point or [Close/Undo]: @50<90 [Enter] amy/khk/jke/puo EC2.5
  • 6. EC202-Computer Aided Design Step 4: Specify next point or [Close/Undo]: @100<180 [Enter] Step 5: Specify next point or [Close/Undo]: C [Enter] OR Specify next point or [Close/Undo]: 50<270 [Enter] The distance is the length of the line to be drawn, followed by the symbol (<) and next followed by the desired angle of the line. PART B: EXERCISE 1. Create a new drawing space using the Metric measurement. 2. Display the grid to the extent of the drawing limits. 3. From the diagram in Fig. 2.5 given below, redraw to full scale: i. Using Absolute Coordinate System  The start point is at coordinates X,Y = 20,30 ii. Using Relative Coordinate System  The start point is at coordinates X,Y = 160,30 iii. Using Polar Coordinate System  The start point is at coordinates X,Y = 90,120 4. Fill in the data entries of each technique into Table 2.1 as at page EC2.7. 5. Save the drawing file and exit AutoCAD. 6. Fig. 2.5 amy/khk/jke/puo EC2.6
  • 7. EC202-Computer Aided Design amy/khk/jke/puo EC2.7 (10 Marks ) RESULT : Data Entries Absolute Coordinate System Relative Coordinate System Polar Coordinate System Command Line [Enter] Line [Enter] Line [Enter] Specify Start Point: (Pt 1) 20,30 160,30 90,120 Specify Next Point: (Pt 2) Specify Next Point: (Pt 3) Specify Next Point: (Pt 4) Specify Next Point: (Pt 5) Specify Next Point: (Pt 6) Specify Next Point: (Pt 7) Specify Next Point: (Pt 8) Specify Next Point: (Pt 9) Specify Next Point: (Pt 10) Specify Next Point: (Pt 11) Specify Next Point: (Pt 12) Specify Next Point: (Pt 13) Specify Next Point: (Pt 14) Specify Next Point: (Pt 15) Specify Next Point: (Pt 16) Specify Next Point: (Pt 17) Table 2.1
  • 8. EC202-Computer Aided Design amy/khk/jke/puo EC2.8 (2 Marks ) (2 Marks ) (4 Marks ) (2 Marks ) DISCUSSION: 1. In the last step of the procedure to complete drawing each figure, you might have type the alphabet ‘C’ or you might have key-in the data for the end value. Explain the difference between them. a. Specify next point or [Close/Undo]: (Keying the alphabet C for close command) …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… b. Specify next point or [Close/Undo]: (Keying the data for end value) …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… QUESTION : 1. When selecting the Line command, which of the AutoCAD input commands do you used frequently? Give a reason for your answer. ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… REFLECTION: At the end of this practical work, I have learnt that: ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… …………………………………………………………………………………………………
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