# engt 122 – cad i chapter 3 – draw commands. outline chapter 3 – draw commands drawing arcs...

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ENGT 122 CAD I Chapter 3 Draw Commands Slide 2 Outline Chapter 3 Draw Commands Drawing Arcs Drawing Rectangles Drawing Ellipses Drawing Polygons Drawing Polylines Drawing Points Slide 3 Drawing Arcs Arc A portion of a circle. There are 11 different methods for creating an arc which involve various combinations of the following inputs; Start Point End Point Intermediate Point Center Point Radius Included Angle Chord Length Start Interm. End Center Center Radius Angle Chord Why so many options?Why so many options? How do you know which is the start point and which is the end point?How do you know which is the start point and which is the end point? Slide 4 Drawing Arcs Arc commands issued from Command line and Toolbar are identical. Both require interactive data input and option selection using the keyboard. For Arc command issued from drop down menu options are pre-selected. Input data is input sequentially according to the prompts no additional option selection is required. Slide 5 Drawing Arcs 3-Point (default method) Input: Start Point, Intermediate Point, End Point. P1P2 P3 Command: ARC Specify start point of arc or [Center]: P1 Specify second point of arc or [Center/End]: P2 Specify end point of arc: P3 *Note: arc direction determined by 2 nd point. May go CW or CCW. P1 P2 P3 Slide 6 Demo 0: Open file Demo-Arcs.dwg. Demonstrate 3-Point ARC command. Slide 7 Exercise 1: Draw the two arcs shown using the 3 Point option. Points can be entered by absolute coordinates, relative coordinates, or a mixture of both. If you have time, try to generate a circle from a single 3 point arc. Notice the limitations? Grid spacing = 1 unit Origin (0,0) Slide 8 Drawing Arcs Start, Center, End Input: Start Point, Center Point, End Point. Arc is drawn from start to end about center. Radius = distance from Start to Center point. End Point not necessarily on arc. Command: ARC Specify start point of arc or [Center]: P1 Specify second point of arc or [Center/End]: C Specify center point of arc: P2 Specify end point of arc or [Angle/chord Length]: P3 P1P2 P3 Slide 9 Drawing Arcs Center, Start, End Input: Center Point, Start Point, End Point. Same as (Start, Center, End) option except for order of input. Command: ARC Specify start point of arc or [Center]: C Specify center point of arc: P1 Specify start point of arc: P2 Specify end point of arc or [Angle/chord Length]: P3 P1P2P3 Slide 10 Drawing Arcs Start, Center, Angle Input: Start Point, Center Point, Included Angle. Radius = distance from Start to Center point. Pos. Angle - arc is drawn from start about center. Neg. Angle - arc is drawn from start about center. Command: ARC Specify start point of arc or [Center]: P1 Specify second point of arc or [Center/End]: C Specify center point of arc: P2 Specify end point of arc or [Angle/chord Length]: A Specify included angle: 3 P1P2 3333 Slide 11 Drawing Arcs Center, Start, Angle Input: Center Point, Start Point, Included Angle. Same as (Start, Center, Angle) option except for order of input. Command: ARC Specify start point of arc or [Center]: C Specify center point of arc: P1 Specify start point of arc: P2 Specify end point of arc or [Angle/chord Length]: A Specify included angle: 3 P1P2 3333 Slide 12 Demo 1: Open file Demo 1.dwg. Demonstrate ARC command: 3 Point Start, Center, End Center, Start, End Start, Center, Angle Center, Start, Angle Slide 13 Drawing Arcs 3-Point Arc P1P2 P3 P1P2 P3 St, C, Ang or C, St, Ang Radius = P1 to P2 Pos. Angle from P1 Neg. Angle from P1 St, C, End or C, St, End Radius = P1 to P2 Arc from P1 P1P2 3333 Quick Review Slide 14 Exercise 2: Create the pink objects shown. For the arcs, use the indicated arc command options. Use Relative Coordinates as much as possible. 12345 1 2 3 4 5 0 Grid spacing = 1 unit 0 3-Point St,C,End St,C,Angle Slide 15 End Lesson 7 Slide 16 Drawing Arcs Start, Center, Length Input: Start Point, Center Point, Chord Length. Radius = distance from Center to Start point. Arc is always drawn from start about center. Pos. Chord Minor Arc (< 180 ). Neg. Chord Major Arc (> 180 ). Command: ARC Specify start point of arc or [Center]: P1 Specify second point of arc or [Center/End]: C Specify center point of arc: P2 Specify end point of arc or [Angle/chord Length]: L Specify length of chord: L3 P1 P2 L3 L3 Positive - Minor Arc Slide 17 Drawing Arcs Start, Center, Length Arc always from start point. Extent of arc depends on sign of Chord Length. P1 P2 L3 Pos. Length L3 Minor Arc P1 P2 L3 Neg. Length L3 Major Arc Slide 18 Drawing Arcs Center, Start, Length Input: Center Point, Start Point, Chord Length. Same as (Start, Center, Length) option except for order of input. Command: ARC Specify start point of arc or [Center]: C Specify center point of arc: Center Specify start point of arc: Start Specify end point of arc or [Angle/chord Length]: L Specify length of chord: Length P1 P2 L3 L3 Positive - Minor Arc Slide 19 Exercise 3: Draw a line from (4,2) to (4,6). This is the chord of the 2 arcs shown. Use the Cntr,St,Length option to draw the blue minor arc. Then use the Cntr,St,Length option to draw the red major arc that completes the first arc to form a full circle. (4,2) Center=(3,4) Chord = 4 (4,6) Slide 20 For Minor Arc: Command: ARC Specify start point of arc or [Center]: C Specify center point of arc: 3,4 Specify start point of arc: 4,2 Specify end point of arc or [Angle/chord Length]: L Specify length of chord: 4 Exercise 3: Solution For Major Arc: Command: ARC Specify start point of arc or [Center]: C Specify center point of arc: 3,4 Specify start point of arc: 4,6 Specify end point of arc or [Angle/chord Length]: L Specify length of chord: -4 (4,2) Center=(3,4) Chord = 4 (4,6) Slide 21 Drawing Arcs Start, End, Angle Input: Start Point, End Point, Included Angle. Pos. Angle - arc is drawn from start to end. Neg. Angle - arc is drawn from start to end. Command: ARC Specify start point of arc or [Center]: P1 Specify second point of arc or [Center/End]: E Specify end point of arc: P2 Specify center point of arc or [Angle/Direction/Radius]: A Specify included angle: 3 P1 P2 3333 Slide 22 Drawing Arcs Start, End, Direction Input: Start Point, End Point, Starting Direction. Starting Direction gives starting direction for arc by specifying direction of a tangent line. Starting Direction defined by angle (with respect to pos. x-axis) or point defining line direction from Start Point. Start direction determines or arc. Command: ARC Specify start point of arc or [Center]: P1 Specify second point of arc or [Center/End]: E Specify end point of arc: P2 Specify center point of arc or [Angle/Direction/Radius]: D Specify tangent direction for the start point of arc: 3 P1 P2 3333 Slide 23 Demo 2: Open file Demo 2.dwg. Demonstrate Start, End, Direction option for ARC command to achieve tangency. Slide 24 Exercise 4: Draw the red line. Then use the Start,End,Direction option of the ARC command to create an arc tangent to the line and through the given point. If you have time, use the same options to complete the circle. Point 123456 1 2 3 4 5 6 7 7 Slide 25 Create the yellow arc using the Start, End, Direction option. Use the following data; Start Point P1 = (4,2) End Point P2 = (5,8) Direction Angle = 30 Then create the pink arc using the Start, End, Direction option which completes the circle. Exercise 5: P1P230 Slide 26 Exercise 5: Solution P1P230 Create the yellow arc using the Start, End, Direction option. Use the following data; Start Point P1 = (4,2) End Point P2 = (5,8) Direction Angle = 30 Then create the pink arc using the Start, End, Direction option which completes the circle. Command: Arc Specify start point of arc or [Center]: 4,2 Specify second point of arc or [Center/End]: E Specify end point of arc: 5,8 Specify center point of arc or [Angle/Direction/Radius]: D Specify tangent direction for the start point of arc: 210 Slide 27 Drawing Arcs Start, End, Radius Input: Start Point, End Point, Radius. Arc always from Start point. Positive Radius Minor Arc. Negative Radius Major Arc. Command: Arc Specify start point of arc or [Center]: P1 Specify second point of arc or [Center/End]: E Specify end point of arc: P2 Specify center point of arc or [Angle/Direction/Radius]: R Specify radius of arc: Rad P1 P2 +Rad. -Rad Major Arc Minor Arc Slide 28 Demo3/Exercise: Draw the green & red objects by creating each segment in the order shown; A first, then B, etc. Use the @ symbol to snap to the previous point. For arcs B and D use St,End,Dir A B C D E F Start Point *This is a demo/exercise using Demo3.dwg For arc F use St,End,Rad. Proceed carefully to avoid any mistakes!!! Slide 29 End Lesson 8 Slide 30 Drawing Arcs (11) Continue Option Input: End Point Only. Requires a pre-existing line or arc. Arc is drawn tangent to end point of previous line or arc and ends at defined point. Command: Arc Specify start point of arc or [Center]: [Enter] Specify end point of arc: P1 P1 P1 Pre-ExistingLine Pre-ExistingArc *Note - A line can be drawn tangent to a pre-existing arc using the same concepts. Slide 31 Demo: Show Continue option for Arc. Pre-existing arc. Pre-existing line. Show Continue option for Line. Pre-existing arc. Pre-existing line. Show difference between continue option [Enter] versus @[Enter]. Slide 32 Exercise 6: For the S use Start,End,Radius for the blue arc. Then complete the figure using the Continue option for the pink arc. If you have time, create the curly cue using a 3-point arc to start the figure and multiple continue options to complete the figure. Slide 33 Exercise 7: Create the drawing shown using the indicated arc options. Use relative coordinates when possible. Slide 34 Drawing Rectangles 3 Methods to specify a Rectangle: Default - specify by 2 diagonal corner points. Area specify area and