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ENGT 122 – CAD I

ENGT 122 – CAD I. Chapter 3 – Draw Commands. Outline Chapter 3 – Draw Commands. Drawing Arcs Drawing Rectangles Drawing Ellipses Drawing Polygons Drawing Polylines Drawing Points. Center. Angle. Drawing Arcs.

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ENGT 122 – CAD I

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  1. ENGT 122 – CAD I Chapter 3 – Draw Commands

  2. Outline Chapter 3 – Draw Commands • Drawing Arcs • Drawing Rectangles • Drawing Ellipses • Drawing Polygons • Drawing Polylines • Drawing Points

  3. Center Angle Drawing Arcs • Arc (A portion of a circle) - There are 11 8 different methods for creating an arc. We will explore 6. Each involves various combinations of the following inputs; • Start Point • End Point • Intermediate Point • Center Point • Radius • Angle Start End Center Radius Interm. • Why so many options? • How do you know which is the start point and which is the end point?

  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 ribbon menu  options are pre-selected. Input data is input sequentially according to the prompts  no additional option selection is required.

  5. P1 P3 P2 P2 P1 P3 Drawing Arcs  3-Point (default method) • Input: Start Point, Intermediate Point, End Point. *Note: arc direction determined by 2nd point. May go CW or CCW. 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

  6. Demo 0: • Open file Demo-Arcs.dwg. • Demonstrate 3-Point ARC command.

  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)

  8. P1 P3 P2 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

  9. P2 P3 P1 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

  10. P1 P2 Ө3 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

  11. P2 P1 Ө3 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

  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

  13. P1 P3 P2 P1 P3 P1 P2 P2 Ө3 Drawing Arcs Quick Review • 3-Point Arc • St, C, EndorC, St, End Radius = P1 to P2 Arc  from P1 • St, C, AngorC, St, Ang Radius = P1 to P2 Pos. Angle  from P1 Neg. Angle  from P1

  14. Exercise 2: • Create the pink objects shown. For the arcs, use the indicated arc command options. • Use Relative Coordinates as much as possible. 5 Grid spacing = 1 unit 3-Point 4 3 2 St,C,End 1 St,C,Angle 0 0 1 2 3 4 5

  15. P2 P1 Ө3 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

  16. Demo 2: • Open file Demo 2.dwg. • Demonstrate Start, End, Direction option for ARC command to achieve tangency.

  17. End Lecture 6

  18. Exercise 3: • 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. 7 Point 6 5 4 3 2 1 0 1 2 3 4 5 6 7

  19. Exercise 4: 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 = 30º Then create the pink arc using the Start, End, Direction option which completes the circle. 5,8 P2 30 P1 4,2

  20. Exercise 4: Solution 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 = 30º Then create the pink arc using the Start, End, Direction option which completes the circle. 5,8 P2 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 30 P1 4,2

  21. P2 +Rad. -Rad P1 Drawing Arcs  Start, End, Radius • Input: Start Point, End Point, Radius. • Arc always  from Start point. • Positive Radius  Minor Arc. • Negative Radius  Major Arc. Minor Arc 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

  22. P1 P1 Pre-Existing Arc Pre-Existing Line Drawing Arcs  Continue Option • Input: End Point Only. • Requires a pre-existing line or arc. • Arc is drawn tangent to end point of last line or arc and ends at defined point. Command: Arc Specify start point of arc or [Center]: [Enter] Specify end point of arc: P1 *Note - A line can be drawn tangent to a pre-existing arc using the same concepts.

  23. 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].

  24. Exercise 5: • 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.

  25. Exercise 6: • Create the drawing shown using the indicated arc options. Use relative coordinates when possible.

  26. Demo3/Exercise: Time Allowing • 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 • For arc F use St,End,Rad. • Proceed carefully to avoid any mistakes!!! B Start Point A C F *This is a demo/exercise using Demo3.dwg E D

  27. End Lecture 7

  28. Drawing Rectangles • In AutoCAD, a rectangle is a single object consisting of 4 groupedlines. Must “Explode” before single line can be erased or modified. • 4 methods to specify a rectangle. We will look at 3: • Default (corner method) • Area • Dimensions • Rotation

  29. P2 P1 Drawing Rectangles Default (Corner) Method: The Default method specifies 2 diagonal corner points. Command: RECTANGLE Specify first corner point or [Chamfer/Elevation/Fillet/Thickness/Width]: P1 Specify other corner point or [Area/Dimensions/Rotation]: P2

  30. Demo: • Rectangles: Load Demo-Rectang.dwg • Draw default 2 Point Rectangle. • Explode rectangle • Demo additional methods as discussed: • Draw Dimension Rectangle. • Draw Rotation Rectangle • Skip other options (Chamfer, Fillet, etc)

  31. Drawing Rectangles Dimension Method: Command: RECTANGLE Specify first corner point or [Chamfer/Elevation/Fillet/Thickness/Width]: P1 Specify other corner point or [Area/Dimensions/Rotation]: D Specify length for rectangles <5.0000>: Length Specify width for rectangles <3.0000>: Width Specify other corner point or [Area/Dim/Rot]: P2 (flips rect.) P2 Alternate P2 Width Length P1 Alternate P2 Alternate P2

  32. P2 Width Length Angle P1 Drawing Rectangles Rotation Method: Command: RECTANGLE Specify first corner point or [Chamfer/Elevation/Fillet/Thickness/Width]: P1 Specify other corner point or [Area/Dimensions/Rotation]: R Specify rotation angle or [Pick points] <45>: Angle Specify other corner point or [Area/Dimensions/Rotation]: (or points defining angle) Note: The rotation angle is retained for subsequent rectangles. Be sure to reset the value to zero if standard rectangle is desired.

  33. Drawing Rectangles Other Options for Self Exploration: • Chamfer – creates chamfered rectangle. • Must supply Chamfer size. • Fillet - creates filleted rectangle. • Must supply fillet size. • Width – line width can be input. • Must supply line width. *NOTE:Values for Chamfer, Fillet, Width, and Rotation are retained for subsequent rectangles. Be sure to reset these values to 0 if standard rectangle is desired.

  34. Exercise 7: • Draw the green Rectangle by Corner Point Method: • 6” long and 4” wide with lower left corner at (1,1). • Draw the pink Rectangle using the Dimension option: • 4” long and 2” wide with 1st corner at (6,4). • Draw the blue Rectangle by Rotation Method. • First corner at (2,5) • If you have time, experiment with Fillet and Chamfer Options. first corner (6,4) first corner (1,1)

  35. CENTER Drawing Ellipses: • An Ellipse is a circle viewed at an angle. • The components of an ellipse are shown. • To initiate an ellipse; • Command:ELLIPSE • Draw Tool Bar: • Ribbon Menu:

  36. Demo 4: • Visualizing an ellipse as a rotated circle: • Load file Demo 4.dwg • Rotate using 3DFORBIT about x-axis. Circular cylinders and holes appear as ellipses when rotated into an isometric view.

  37. Major Axis P3 half length P1 P2 Center Minor Axis Drawing Ellipses: • Specify End Points (P1, P2) for one axis (major or minor) and Half Length of other axis. • If using coordinate input for P3, Half Length is distance from ellipse center to P3 Axis & Half Width Method: (center is ref for relative coords) Command: ELLIPSE Specify axis endpoint of ellipse or [Arc/Center]: P1 Specify other endpoint of axis: P2 Specify distance to other axis or [Rotation]: Half Length or P3

  38. Demo: • Ellipse: Load Demo-Ellipse.dwg • Axis & Half Width Method • Next demo show Axis & Rotation Method • Next demo show Center & Axis Method

  39. Drawing Ellipses: 0º Axis & Rotation Method: • Specify End Points for Major axis and rotation angle of circle about Major axis. 45º Major Axis 90º P1 P2 Angle – Enter angle value (0° - 89.4°) or use mouse as lever arm to dynamically rotate about major axis. Center Minor Axis Command: ELLIPSE Specify axis endpoint of ellipse or [Arc/Center]: P1 Specify other endpoint of axis: P2 Specify distance to other axis or [Rotation]: R Specify rotation around major axis: Angle

  40. Exercise 9: • 1)Draw the red ellipse whose major axis is 4” and whose rotation angle around this axis is 60º. • 2)Draw the green ellipse whose major axis is 4” and whose rotation angle around the major axis is 15º. • 3) Draw the yellow ellipse with a Major axis of 4” and a Minor axis of 2 units. This ellipse should be identical to the first ellipse from the exercise. Confirm this using the MOVE command to place one approximately on top of the other. 2 1 3

  41. Major Axis P3 half length P2 P1 Center Minor Axis Drawing Ellipses: Center & Axes Method: • Similar to other methods but first axis defined by center and one End Point (instead of axes ends). Command: ELLIPSE Specify axis endpoint of ellipse or [Arc/Center]: C Specify center of ellipse: P1 Specify endpoint of axis: P2 Specify distance to other axis or [Rotation]: Half Lengthor P3

  42. End Lecture 8

  43. Drawing Regular Polygons: 3 Sides 4 Sides • Regular Polygon – A closed planar figure with straight sides of equal length and equal angles. Sides are grouped as a single object (3 to 1024 sides). • To initiate a Polygon; • Command:POLYGON • Draw Tool Bar: • Ribbon Menu: 6 Sides 5 Sides 8 Sides

  44. Inscribed Circumscribed P1 P1 Rad Rad Drawing Polygons: Corner to corner distance known Flat to flat distance known Center Method #1: • Specify # Sides. • Polygon based on a circle: • Specify Center (P1). • Specify whether Inscribed or Circumscribed. • Give value for circle Radius: • Base edge aligns with x-axis. Command: POLYGON Enter number of sides <6>: 6 Specify center of polygon or [Edge]: P1 Enter an option [Inscribed in circle/Circumscribed about circle] <I>: Ifor inscribed, Cfor circumscribed Specify radius of circle: Radius

  45. Demo 5: • POLYGONS: • Load file Demo5.dwg • Show Center Method #1 Inscribed Vs. Circumscribed. • Show Explode command • Next Demo – Show Center Method #2 • Next Demo - Show Edge Option

  46. P2 P2 P1 P1 Inscribed Circumscribed P2 P2 P1 P1 Drawing Polygons: Controls Polygon Orientation Center Method #2: • Specify # Sides. • Specify Center (P1). • Specify Inscribed/Circumscribed. • Specify Radius of circle by point input P2: • Inscribed – Corner of polygon placed at point P2. • Circumscribed – Midpoint of polygon edge placed at point P2. Command: POLYGON Enter number of sides <6>: 6 Specify center of polygon or [Edge]: P1 Enter an option [Inscribed in circle/Circumscribed about circle] <I>: Ifor inscribed, Cfor circumscribed Specify radius of circle: P2

  47. Exercise 10: • Draw the circles shown in red at the given center locations (Radius = 2”). • Then draw the green polygons using Center Method #2. Center=(2,4) Center=(8,4)

  48. Drawing Regular Polygons: Edge Method: • Specify number of Sides. • Specify End Points (P1, P2) for first edge. • End points determine edge direction, and polygon created in  direction. P2 Edge Direction Polygon Direction P1 Command: POLYGON Enter number of sides <4>: Sides Specify center of polygon or [Edge]: E Specify first endpoint of edge: P1 Specify second endpoint of edge: P2

  49. Drawing Polylines: • Polyline – A series of interconnected lines and arcs with special properties and controllable width. To initiate a Polyline; • Command:PLINE • Draw Tool Bar: • Ribbon Menu:

  50. Drawing Polylines: • A polyline is formed as a single object comprised of line and arc segments. • Primary options: • Line – line mode creates straight line segments • Arc – arc mode creates polyarc segments Depending on the primary option, a different set of sub-options appear for object creation. • Secondary options: • Line Width (for start & end of segment) • Additional options for defining geometry

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