autoCad introduction

21. Learning Objectives Once you know the coordinates of the points, you can generate the drawing by using AutoCAD’s LINE command and entering the coordinates of the points. Command: LINE « Specify first point: 1.5,1.75 « (Start point.) Specify next point or [Undo]: @1<90 « Specify next point or [Undo]: @2.0<0 « Specify next point or [Close/Undo]: @2<30 « Specify next point or [Close/Undo]: @0.75<0 « Specify next point or [Close/Undo]: @1.25<-90 « Example 3 Specify next point or [Close/Undo]: @1.0<180 « Specify next point or [Close/Undo]: @0.5<270 « Specify next point or [Close/Undo]: @1.0<0 « Specify next point or [Close/Undo]: @1.25<270 « Specify next point or [Close/Undo]: @0.75<180 « Specify next point or [Close/Undo]: @2.0<150 « Specify next point or [Close/Undo]: C « (Joins the last point with the first point.) Save this drawing by entering SAVE at the Command prompt and then press ENTER. The Save Drawing As dialog box is displayed. Enter the name Exam3 in the File name edit box to replace Drawing1.dwg and then choose the Save button. The drawing will be saved with the given name in the My Documents directory.

25. Learning Objectives The following is the Command prompt sequence for drawing the object in the figure : Command: LINE Specify first point: 2,2 Specify next point or [Close/Undo]: 2 « (Move the cursor horizontally and enter the length of the line, 2, from the keyboard.) Specify next point or [Close/Undo]: .7071 (Select POLAR in the status bar and position the cursor in a 45-degree direction and enter .7071.) Specify next point or [Close/Undo]: 1 Move the cursor up vertically, then enter 1. Specify next point or [Close/Undo]: 3 Move the cursor left horizontally, then enter 3 . Specify next point or [Close/Undo]: 1 Move the cursor down vertically, then enter 1 . Specify next point or [Close/Undo]: C Example 4

39. Learning Objectives Tangent, tangent, radius ( Ttr ) option Drawing a circle using the tangent , tangent , radius ( Ttr ) option

40. Learning Objectives Tangent , tangent , radius option Tangent , tangent , radius ( Ttr ) option CIRCLE Options

51. Learning Objectives If you choose the Engineering or Architectural format, you can enter the distances or coordinates in any of the five formats. In the following example, the units are set as architectural; hence, different formats are used to enter the coordinates of points: Command: LINE « Specify first point: 1-3/4,3/4 « ( Fractional .) Specify next point or [Undo]: 1’1-3/4&quot;,3-1/4 « ( Architectural .) Specify next point or [Undo]: 0’10.375,0’8.75 « ( Engineering .) Specify next point or [Close/Undo]: 0.5,4-1/4&quot; « ( Decimal and engineering .)

53. In AutoCAD, by default the angles are positive if measured in the counterclockwise direction and the angles are measured from the positive X axis, see East. The angles are negative if measured clockwise. N, S, E, W directions Measuring angles counterclockwise from the positive X axis(default) Learning Objectives

54. Learning Objectives When you choose the Direction button in the Drawing Units dialog box, the Direction Control dialog box appears which gives you an option of selecting the setting for direction of the Base Angle. If you select the Other option, you can set your own direction for the Base Angle by either entering a value in the Angle edit box or choosing the Pick an Angle button to specify the angle on the screen. You can also set the units of measure while inserting a block from the AutoCAD DesignCenter. In the Drawing Units dialog box choose any measuring unit from the When inserting blocks in this drawing, scale them to drop-down list. Now while inserting a block from the DesignCenter, AutoCAD inserts the block with the chosen unit. Selecting units for inserting the DesignCenter blocks Setting direction from the Direction Control dialog box

59. Learning Objectives Assume, for example, that you have changed the current settings and made the system of angle measure radians with two places of precision: angle base north (the Y axis), and the direction clockwise. Now, if you enter <1.04 or <1.04r, all the current settings will be taken into consideration and you will get an angle of 1.04 radians, measured in a clockwise direction from the positive Y axis, Figure (a). If you enter <<60, AutoCAD will bypass the current settings and reference the angle in degrees from the positive X axis, measuring 60 degrees in a counterclockwise direction, Figure (b). If you enter <<<1.04r, AutoCAD will use the current angular units, but will bypass the current angle base and angle direction. Hence, the angle will be referenced from the positive X axis, and will be measured 1.04 radians in a counterclockwise direction, Figure (c). Forcing default angles

66. Learning Objectives Example 6 Calculate limits Scale factor = 1&quot; = 48&quot; or 1&quot; = 4' The length of the sheet is 12&quot; Therefore, X limit = 12 x 4' = 48' Also, Y limit = 9 x 4' = 36' Calculate scale factor A line 31' long will be = 31'/4' = 7.75&quot; on paper. Similarly, a line 21' long = 21'/4' = 5.25&quot;. Approximate space between the drawing and the edges of paper = 2&quot; Therefore, total length of the sheet = 7.75 + 2 + 2 = 11.75&quot; Similarly, total width of the sheet = 5.25 + 2 + 2 = 9.25&quot;

73. Learning Objectives 6. In AutoCAD, you can enter values for the plot scale from the Plot scale area. Clear the Fit to paper check box if selected and then open the Scale drop-down list to display the various scale factors. From this list, you can select a scale factor you want to use. For example, if you select the scale factor 1/4&quot; = 1'-0&quot;, the edit boxes available below the drop-down list will show 1 inch = 48 units. If you want the drawing to be plotted so that fit fits on the specified sheet of paper, select the Fit to paper check box. When you select this check box, AutoCAD will determine the scale factor and display the scale factor in the edit boxes. In this example, you will plot the drawing so that it scales to fit the paper. Therefore, select the Fit to paper check box and notice the change in the edit boxes. You can also enter your own values in the edit boxes. Example 7

82. Learning Objectives 1. Choose Tools > Options from the menu bar to invoke the Options dialog box. You can also right-click in the drawing area to display the shortcut menu and choose Options to invoke this dialog box. 2. Choose the Profiles tab and then choose the Add to List button to display the Add Profile dialog box. Enter the name of the new profile as Myprofile1 and a description of the new profile, and then choose the Apply & Close button to exit. 3. Select Myprofile1 profile and then choose the Set Current button to make Myprofile1 current. You will notice that the Current Profile name above the tabs changes from <<Unnamed Profile>> to Myprofile1 . 4. Choose the Display tab and then choose the Colors button. The Color Options dialog box is displayed. Select the Model tab background option from the Window Element drop-down list. Select White from the Color drop-down list, see figure

83. Color Options dialog box with the Options dialog box Learning Objectives Example 4 5. Choose the Drafting tab and change the AutoSnap Marker Size to the maximum using the slider bar. Choose the Apply button and then the OK button to exit the dialog box.

84. Learning Objectives Example 4 7. Invoke the Options dialog box again and choose the Profiles tab. Double-click on the default profile (<<Unnamed Profile>>) to reload the default settings. The screen settings will change as specified in the default profile. 6. Draw a line and then choose the OSNAP button from the status bar. Again invoke the LINE command and move the cursor on the previously drawn line; a marker is displayed and the endpoint, notice the size of the marker now.