Editing Polylines1 Sacramento City College Engineering Design Tecnology

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.

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

Editing Polylines4 The PLINE Command

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.

Editing Polylines6 PLINE Command - The Arc option

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.

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.

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.

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.

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).

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

Editing Polylines13

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.

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])

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.

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.

Editing Polylines18 Three-Point Polyline Arc

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

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.

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

Editing Polylines22 Presetting Polyline Widths The PLINEWID System Variable

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.

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

Editing Polylines25 Editing Polylines

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.

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.

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.

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.

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.

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.

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

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.

Editing Polylines34 Opening and Closing a Polyline

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.

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.

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.

Editing Polylines38 Joining Polylines to Other Polylines

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.

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

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.

Editing Polylines42 Changing the Polyline Width

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.

Editing Polylines44 Editing a Polyline Vertex

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.

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.

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.

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

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.

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.

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.

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)

Editing Polylines53 Making Breaks in a Polyline

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.

Editing Polylines55 Inserting a New Polyline Vertex

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.

Editing Polylines57 Moving a Polyline Vertex

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.

Editing Polylines59 Straightening Polyline Segments or Arcs

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.

Editing Polylines61 Changing Polyline Segment Widths

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.

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.

Editing Polylines64 Making Smooth Curves

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.

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

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

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.

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.

Editing Polylines70 The PEDIT Spline Option

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

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).

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

Editing Polylines74 Straightening All Polyline Segments

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.

Editing Polylines76 The Undo Option

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.

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.

Editing Polylines79 The SPLINE Command

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”.

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.

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

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.