1. Editing Polylines1 Sacramento City College Engineering Design Tecnology

2. Editing Polylines2 Objectives u Use the PLINE command to draw polylines and polyarcs. u Edit existing polylines with the PEDIT command. u Describe the function of each PEDIT command option. u Use the EXPLODE command to change polylines into individual line and arc segments.

3. Editing Polylines3 Objectives u Draw and edit spline curves. u Create a polyline boundary.

4. Editing Polylines4 The PLINE Command

5. Editing Polylines5 PLINE Command u The PLINE command can be accessed by: u Picking the Polyline button in the Draw toolbar u OR u Selecting Polyline from the Draw pull-down menu u OR u Type PL or PLINE at the Command: prompt.

6. Editing Polylines6 PLINE Command - The Arc option

7. Editing Polylines7 PLINE Command u The Arc option of the PLINE command u Is similar to the ARC command u The PLINE Width and Halfwidth options can be used to set an arc width. u The arc width can range from 0 up to the radius of the arc.

8. Editing Polylines8 PLINE Command u A polyline arc with different end widths is drawn by u accessing the Width option and u changing the width values.

9. Editing Polylines9 Drawing a Continuous Polyline Arc u A polyline arc continued from a previous line or polyline is tangent to the last object drawn. u The arc's center is determined automatically u You can pick a new center.

10. Editing Polylines10 Drawing a Continuous Polyline Arc u If a straight polyline is continued from a polyline arc, the arc's tangent direction remains the same as that of the previous line, arc, or polyline. u This may not be what you want. u Specify a different setting with one of the PLINE Arc options.

11. Editing Polylines11 Drawing a Continuous Polyline Arc u Arc Options: u Angle u Center u Close u Direction u Radius u Second pt (second point).

12. Editing Polylines12 Specifying the Included Angle u Angle option u You can specify the angle for a PLINE arc by using the Angle option.

13. Editing Polylines13

14. Editing Polylines14 Specifying the Included Angle u Center option u When a polyline arc is continued from a drawn object, the center point is calculated automatically. u You can to pick a new center point. u The CEnter option allows you to specify a new center point for the arc.

15. Editing Polylines15 Specifying the Included Angle u If A is entered, the next prompt is: u Specify included angle: (enter an included angle and press [Enter]) u If L is entered, the next prompt is: u Specify length of chord: (enter a chord length and press [Enter])

16. Editing Polylines16 The Direction Option u The Direction option u changes the bearing of the arc. u It changes the default option of placing a polyline arc tangent to the last polyline, arc, or line. u The Direction option functions much like the Direction option of the ARC command.

17. Editing Polylines17 Drawing a Polyline Arc by Radius u Radius Option u Polyline arcs can be drawn by giving the arc's radius. u Enter the Radius option inside the PLINE Arc command.

18. Editing Polylines18 Three-Point Polyline Arc

19. Editing Polylines19 Three-Point Polyline Arc u A three-point polyline arc can be drawn by using the Second pt option.

20. Editing Polylines20 Three-Point Polyline Arc u The CLose option u adds the last segment to close a polygonal shape. u Used inside the PLINE Arc command sequence closes the shape with a polyline arc segment, rather than a straight polyline.

21. Editing Polylines21 Three-Point Polyline Arc u Two letters are required u CL = CLose u CE = CEnter option.

22. Editing Polylines22 Presetting Polyline Widths The PLINEWID System Variable

23. Editing Polylines23 Presetting Polyline Widths u The PLINEWID system variable u Sets the constant width for polylines. u To change a PLINE width u Enter PLINEWID at the Command: prompt and u enter a new value.

24. Editing Polylines24 Presetting Polyline Widths u Polygons u are NOT affected by the PLINEWID system variable.

25. Editing Polylines25 Editing Polylines

26. 26 Editing Polylines u Polylines are drawn as single segments. u Even though you draw connecting segments, AutoCAD puts them all together. u The result is one polyline treated as a single object.

27. Editing Polylines27 Editing Polylines u When editing a polyline, you must u Edit it as one object u OR u Divide it into its individual segments. u This method destroys the PLINE (!) u Not recommended.

28. Editing Polylines28 Editing Polylines u The PEDIT (PE) command is accessed by: u Picking the Edit Polyline button from the Modify II toolbar u OR u By typing PE or PEDIT at the Command: prompt, u OR u By selecting Polyline from the Modify pull- down menu.

29. Editing Polylines29 Editing Polylines u PEDIT u You can also u select a polyline and u then right-click in the drawing area to display a shortcut menu.

30. Editing Polylines30 Editing Polylines u Use the pick box to select a polyline to be edited. u If you use the pick box on a wide polyline, you must pick it on the edge of a polyline segment, rather than in the center.

31. Editing Polylines31 Editing Polylines u If the object you select is a line or arc object (not a polyline), the following message is displayed: u Object selected is not a polyline u Do you want to turn it into one? u Entering Y or pressing [Enter] turns the selected object into a polyline.

32. Editing Polylines32 Editing Polylines u Join Option u Allows a group of connected lines and arcs can be turned into a continuous polyline.

33. Editing Polylines33 Editing Polylines u There is no default option for the PEDIT command u You must enter one of the options. u Pressing [Enter] returns you to the Command: prompt.

34. Editing Polylines34 Opening and Closing a Polyline

35. Editing Polylines35 Opening and Closing a Polyline u Open PLINEs can be Closed. u Closed PLINEs can be Opened. u hese functions are performed with the Open and Close options of the PEDIT command.

36. Editing Polylines36 Opening and Closing a Polyline u If the PLINE is OPEN u It can only be CLOSED u If the PLINE is CLOSED u It can only be OPENed u AutoCAD displays only the appropriate option – NOT both options.

37. Editing Polylines37 Opening and Closing a Polyline u The Open option is not displayed if you select a polyline that was closed by manually drawing the final segment. u It is only available if the polygon was closed using the Close option of the PLINE command.

38. Editing Polylines38 Joining Polylines to Other Polylines

39. Editing Polylines39 Joining Polylines to Other Polylines u Join Option u Allows polylines, lines, and arcs that share an EXACT endpoint can be joined to create a single polyline. u AutoCAD computes line vertices to 25 decimal places u Lines may appear to have the same endpoints, BUT in reality, do NOT. u You CANNOT join objects with PEDIT unless the endpoints match EXACTLY.

40. Editing Polylines40 Joining Polylines to Other Polylines u This option works only if the polyline and other existing objects meet exactly. u They cannot cross. u There cannot be any spaces or breaks between the objects. u Select each object to be joined

41. Editing Polylines41 Joining Polylines to Other Polylines u To get the endpoints to match EXACTLY u You may have to MOVE an object u Turn OSNAP on u And MOVE the object using the ENDPOINT OSNAP to get the endpoints aligned.

42. Editing Polylines42 Changing the Polyline Width

43. Editing Polylines43 Changing the Polyline Width Changing the Polyline Width u The Width Option u of the PEDIT command u allows you to change a polyline width to a new width.

44. Editing Polylines44 Editing a Polyline Vertex

45. Editing Polylines45 Editing a Polyline Vertex Editing a Polyline Vertex u The Edit vertex option of the PEDIT command is used to u Edit polyline vertices and u Points of tangency.

46. Editing Polylines46 Editing a Polyline Vertex Editing a Polyline Vertex u A polyline vertex u is where straight polyline segments meet. u A point of tangency u is where straight polyline segments or polyline arcs join other polyline arcs.

47. Editing Polylines47 Editing a Polyline Vertex Editing a Polyline Vertex u When you enter the Edit vertex option, u an "X" marker u appears on screen at the first polyline vertex or point of tangency.

48. Editing Polylines48 Editing a Polyline Vertex Editing a Polyline Vertex u Next u Previous u Break u Insert u Move u Regen u Straighten u Tangent u Width u eXit The Edit vertex option has 10 options

49. Editing Polylines49 Editing a Polyline Vertex Editing a Polyline Vertex u Next u Moves the "X" marker on screen to the next vertex or point of tangency on the polyline. u Previous u Moves the marker to the previous vertex or point of tangency on the polyline. u Break u Breaks a portion out of the polyline.

50. Editing Polylines50 Editing a Polyline Vertex Editing a Polyline Vertex u Insert u Adds a new polyline vertex. u Move u Moves a polyline vertex to a new location. u Regen u Generates the revised version of the polyline. u Straighten u Straightens polyline segments.

51. Editing Polylines51 Editing a Polyline Vertex Editing a Polyline Vertex u Tangent u Specifies a tangent direction for curve fitting when using the PEDIT Fit option. u Width u Changes a polyline segment width. u eXit u Returns the PEDIT command prompt.

52. Editing Polylines52 Editing a Polyline Vertex Editing a Polyline Vertex u Only the current point identified by the "X" marker is affected by editing functions. u The marker is moved u Clockwise using the Next option (N) u Counterclockwise using the Previous option. (P)

53. Editing Polylines53 Making Breaks in a Polyline

54. Editing Polylines54 Making Breaks in a Polyline Making Breaks in a Polyline u Break option u Breaks out a portion of a polyline u Use the Next or Previous option to move the "X" marker to the correct vertex. u AutoCAD accepts the highlighted vertex as the first break point. u Move the marker to the vertex you want to designate as the second break point. u Enter G for Go. u AutoCAD removes the portion of the polyline between the two selected points.

55. Editing Polylines55 Inserting a New Polyline Vertex

56. Editing Polylines56 Inserting a New Polyline Vertex Inserting a New Polyline Vertex u To add a new vertex u Use the Insert vertex option. u Use the Next or Previous option to locate the vertex next to where you want the new vertex to be.

57. Editing Polylines57 Moving a Polyline Vertex

58. Editing Polylines58 Moving a Polyline Vertex Moving a Polyline Vertex u To move a polyline vertext u Use the Move vertex option. u This option is similar to the Insert option. u Place the "X" marker on the vertex you want to move with Next or Previous. u Then, enter the Move option and u Specify the new location.

59. Editing Polylines59 Straightening Polyline Segments or Arcs

60. Editing Polylines60 Straightening Polyline Segments or Arcs Straightening Polyline Segments or Arcs u The Straighten vertex option u allows you to straighten polyline segments or arcs between two points. u Place the "X" marker on the vertex you want to move with Next or Previous. u Then, enter Straighten option. u If the 'X" marker is not moved before G is entered, AutoCAD straightens the segment from the first marked point to the next vertex.

61. Editing Polylines61 Changing Polyline Segment Widths

62. Editing Polylines62 Changing Polyline Segment Widths Changing Polyline Segment Widths u To change the width of an individual polyline segment u Use the Width vertex option u Move the "X" marker to the beginning vertex of the segment to be altered. u Enter the Width option and u Specify the new width.

63. Editing Polylines63 Changing Polyline Segment Widths Changing Polyline Segment Widths u The starting width default value is the current width of the segment to be changed. u The ending width default value is the same as the revised starting width.

64. Editing Polylines64 Making Smooth Curves

65. Editing Polylines65 Making Smooth Curves Making Smooth Curves u You can convert a polyline into a series of smooth curves. u Example: a graph. u A graph may show a series of plotted points as a smooth curve rather than straight segments. u This process is called curve fitting.

66. Editing Polylines66 Making Smooth Curves Making Smooth Curves u Example: a curved landscape border. u The landscape border can be drawn with straight polyline segments and u then converted to a smooth curve. u If the curvature is not correct, u Decurve the line u Adjust the verticees u Recurve the line

67. Editing Polylines67 Making Smooth Curves Making Smooth Curves u To curve a PLINE u Use the PEDIT u Fit option u Spline option.

68. Editing Polylines68 Making Smooth Curves Making Smooth Curves u The Fit option u allows you to construct pairs of arcs passing through control points. u You can specify the control points u Closely spaced control points produce a smooth curve.

69. Editing Polylines69 Making Smooth Curves Making Smooth Curves u If the resulting curve does not look like what you had anticipated, u Decurve the PLINE u Enter the Edit vertex option. u Make changes using the various vertex editing options as necessary.

70. Editing Polylines70 The PEDIT Spline Option

71. Editing Polylines71 The PEDIT Spline Option u The PEDIT Fit option, u Causes the resulting curve to pass through polyline vertices.

72. Editing Polylines72 The PEDIT Spline Option u The PEDIT Spline option u makes the resulting curve pass through the first and last control points or vertices only. u The curve pulls toward the other vertices (but does not pass through them).

73. Editing Polylines73 The PEDIT Spline Option u The SPLINETYPE system variable u determines whether AutoCAD draws cubic or quadratic curves. u Default = 6 = cubic curve u 5 = quadratic curve

74. Editing Polylines74 Straightening All Polyline Segments

75. Editing Polylines75 Straightening All Polyline Segments u The PEDIT Decurve option u returns a polyline edited with the Fit or Spline options to its original form. u You can also use the Decurve option to straighten the segments of a polyarc.

76. Editing Polylines76 The Undo Option

77. Editing Polylines77 The Undo Option u If you make a mistake while editing a polyline, use the Undo option. u Using the Undo option more than once allows you to step backward through each option used. u Press [Enter] to return to the Command: prompt.

78. Editing Polylines78 The Undo Option u The UNDO command u can also be used at the Command: prompt to undo the effects of the last PEDIT command.

79. Editing Polylines79 The SPLINE Command

80. Editing Polylines80 The SPLINE Command u The SPLINE command u is used to create a special type of curve called a “non-uniform rational B-spline” (NURBS). u A NURBS curve is a “true spline”.

81. Editing Polylines81 The SPLINE Command u To access the SPLINE command: u Pick SPLINE button in the Draw toolbar u OR u Pick SPLINE from the Draw pull-down menu. u OR u Type SPL or SPLINE at the the Command: prompt.

82. Editing Polylines82 Drawing Closed Splines u Use the Close option to draw a closed spline.

83. Editing Polylines83 The Fit Tolerance Specification u Different results can be achieved when drawing splines by altering the specifications used with the Fit Tolerance option.