Autocad Basics 7/28/2009. Chapter 14 - Learning Objectives

Transcription

1 Chapter 14 - Learning Objectives Autocad Basics Chapter 14 July 28, 2009 Use grips to stretch, copy, move, rotate, scale, and mirror objects. Edit objects using the Quick Properties panel and the Properties palette. Use the MATCHPROP tool to match object properties. Edit between drawings. Create selection sets using the Quick Select dialog box. Grips Grips are small boxes that appear at strategic points on an object when you select the object while no tool is active. For example, the grips appear at the endpoints and midpoint of a straight line and at the center and quadrant points of a circle. Selecting Grips To activate grips, move the crosshairs pick box to the desired object and pick. The object is highlighted, and grips are displayed as unselected grips. Unselected grips are considered warm and appear as blue filled-in squares or arrows by default. Moving the crosshairs over a warm grip causes the color of the grip to pink. Pausing over a warm grip and letting it change color ensures that you select the correct grip, especially when multiple grips are close together. Pick the highlighted grip to activate it. A selected grip selected grip is considered hot, and appears as a red filledin square or arrow by default Working with Grips A hot grip can be used to perform a STRETCH, COPY, MOVE, ROTATE, SCALE, or MIRROR operation. If more than one object is selected, displaying warm grips, what you do with the hot grips affects all of the selected objects. Objects having warm and hot grips are highlighted and are part of the current selection set. Working With Grips The [Shift] key may be used to add or remove hot grips. To make a second grip hot, hold the [Shift] key down while selecting both the first and second grip. To add more grips to the hot grip selection set, continue to hold the [Shift] key down and select additional grips. With the [Shift] key held down, selecting a hot (red) grip returns it to the warm (blue) stage. 1

2 Working With Grips Working With Grips Many of the conventional AutoCAD editing operations can be performed when warm grips are displayed on-screen. For example, the ERASE tool can be used to clear the screen of all objects displayed with warm grips by fi rst picking the objects and then selecting the ERASE tool or pressing the [Delete] key. This technique is available when the Noun/verb selection check box is selected in the Options dialog box > Selection tab > Selection Modes area. Autocad Selection Options Grip Tools Grip tools are not selected using traditional ribbon buttons or menu browser options. Instead, select a grip to make the grip hot and activate the grip tools. The first tool is STRETCH, as indicated by the ** STRETCH ** Specify stretch point or [Base point/copy/undo/exit]: prompt. You can use the STRETCH tool at this prompt or select nother grip tool. Press the [Enter] key or the space bar or rightclick and select the Enter option to cycle through additional tool options: ** STRETCH Grip Tools As an alternative to cycling through the tool options, you can right-click to access a grips shortcut menu, which is available only after a hot grip has been activated. The shortcut menu allows you to access the five grip editing options without using the keyboard. A third option to activate t a tool is to enter the first two characters of the desired tool. Type MO for MOVE, MI for MIRROR, RO for ROTATE, SC for SCALE, and ST for STRETCH. Stretching Objects The STRETCH tool is initially active when you make a grip hot. The process of stretching using grips is similar to stretching using the traditional STRETCH tool. The main difference is that the hot grip acts as the base point for the stretch. Move the crosshairs to make the selected object stretch. If you pick the middle grip of a line or an arc, the center grip of a circle, or the insertion point grip of a block, single-line text, multiline text, or table, the object moves instead of stretching. 2

3 Stretching Options Use the Base point option to select a base point anywhere in the drawing to use instead of the hot grip base point. Use the Copy option to activate the copy function of the STRETCH tool. Depending on the hot grip, the Copy option either allows you to produce a copy of the entire selected object, similar to the traditional COPY tool, or a stretched copy of the selected object. Activate the Undo option to undo the previous operation. Choose the exit option to exit the tool. Grip Tools Moving Objects To move an object with grips, select the object, pick a grip to use as the base point, and then right-click and choose the Move menu option or cycle through the tools until you get to the MOVE function. Move the object to a new point by entering or picking the new location. Use grid snaps, coordinate entry techniques, polar tracking, object snaps, or object snap tracking to move the object accurately. Grip Tools Copying Objects The Copy option is included in each of the grip editing tools. If you pick a grip that moves the entire object when using the STRETCH tool, and then activate the Copy option, the stretch functions as a copy. However, the Copy option in the MOVE tool is the true form of the COPY tool, allowing you to copy from any selected grip. The hot grip acts as the copy base point. Create as many copies of the selected object as needed, and then exit the tool. Grip Tools Rotating Objects To rotate an object using grips, pick a grip to use as the base point, and then right-click and choose the Rotate option, or cycle through the tools until you get to the ROTATE function. Then enter a rotation angle. Typically, the rotation angle is input at the keyboard, though other point entry methods can be used to rotate the object accurately. The Undo and exit options function the same when using the ROTATE tool as when using the STRETCH tool. Grip Tools Rotate Options The Reference option can be used when the object is already rotated at a known angle and you want to rotate it to a new angle. The selected base point remains in the same place when the object is rotated. The reference angle is the current angle. If you know the value of the current angle, enter the value at the prompt. Otherwise, pick two points on the reference line to identify the existing angle. Enter a value for the new angle or pick a point. Grip Tools Scaling Objects To scale an object with grips, select the object, pick a grip to use as the base point, and then right-click and choose the Scale option, or cycle through the tools until you get to the SCALE function. Then enter a scale factor or pick a point to increase or decrease the size of the object. The Undo and exit options function the same when using the SCALE tool as when using the STRETCH tool. The Reference option can be used if you know the current length and the desired length. The selected base point remains in the same place when the object is scaled. 3

4 Grip Tools Mirroring Objects To mirror an object with grips, select the object, pick a grip to use as the base point, and then right-click and choose the Mirror option, or cycle through the tools until you get to the MIRROR function. Then pick another grip or any point on the screen as the second point of the mirror line. Grip Tools Mirroring Objects Unlike the standard MIRROR tool, the grips version of the MIRROR tool does not give you the immediate option to delete the old objects. The old objects are deleted automatically. To keep the original object while mirroring, use the Copy option of the MIRROR tool Adjusting Object Properties Every drawing object has specific properties. Some objects, such as lines, have few properties, while other objects, such as multiline text or tables, contain many properties. Properties include geometry characteristics, such as the location of the endpoint of a line in X,Y,Z space, the diameter of a circle, or the area of a rectangle. Modifying Object Prooperties Use the Quick Properties panel or the Properties palette whenever you want to adjust object properties, but especially when you want to modify a particular propertey or set of properties for multiple objects at once. Layer is another property associated with all objects. Adjusting Object Properties The Quick Properties panel is displayed by default whenever you pick an object. The Quick Properties panel always floats and cannot be docked. By default, the panel appears above and to the right of the crosshairs. The drop-down list at the top of the Quick properties panel indicates the type of object selected. Properties associated with the selected object are shown below the drop-down list in rows. Quick Properties Panel 4

5 Quick Properties Panel The Quick Properties panel lists the most common properties associated with the selected objects. You should recognize most of the properties, because these are the same values you used to create the objects. By default, three properties are shown, unless the selected objects contain fewer properties. If more properties are available, hover over the Quick Properties bar on the left side of the panel to expand the list. Quick Properties The way that you change a value depends on the selected property. A text box opens when you select certain properties, such as the Radius property, or the Text height property available when you select a single-line li or multiline text t object. Enter a new value in the text box to change the value of the property. Other properties, such as the Layer property, display a drop-down arrow with a list of values from which to choose. Quick Properties A pick button is available for geometric properties, such as the Center X and Center Y properties shown when you select a circle. Select the button to pick a new coordinate location. Turning Off Quick Properties Quick Properties button on the status bar or typing the [Ctrl]+[Shift]+[P] key combination. Press the [Esc] key when you are finished using the Quick Properties panel. If you pick the Close button in the upper-right corner of the panel, the Quick Properties tool is turned off. Properties Palette The Quick Properties panel provides a quick way to view and modify the most common properties associated with a selected object or objects. The Properties palette provides the same function as the Quick Properties panel, but it allows you to view and adjust all of the properties related to the selected objects. Properties Palette To access the properties palette select the properties palette icon from the palette area of the View tab,or type Properties, Props, CH or MO after the command prompt. It may also be accessed by selecting an object, right clicking and selecting Properties from the shortcut menu. 5

6 Properties Palette The Properties palette is divided into categories. The five categories General, 3D Visualization, Plot style, View, and Misc list the current settings for the drawing. Underneath each category are rows of object properties. Properties Palette The upper-right portion of the Properties palette contains three buttons. Pick the Quick Select button to access the Quick Select dialog box, where you can create object selection sets. Properties Palette Picking the Select Objects button deselects the currently selected objects and changes the crosshairs to a pick box. Properties Palette The third button toggles the value of the PICKADD system variable, which determines whether you need to hold down the [Shift] key when adding objects to a selection set. Adjusting Properties In order to modify an object using the Properties palette, the palette must be open and an object must be selected. For example, if a circle and a line are drawn and you need to modify the circle, either double-click the circle or pick the circle to make the grips appear and then open the Properties palette. Working with properties in the Properties palette is very similar working with properties in the Quick Properties panel. General Properties All objects have a general category in the Properties palette. The general category allows you to modify properties such as color, layer, linetype, linetype scale, plot style, lineweight, 6

7 Properties The layer of a selected object can also be changed by selecting a layer from the Layer Control drop-down down list of the Layers panel of the ribbon. Color, linetype, plot style, and lineweight, can also be adjusted by selecting from the appropriate control drop-down list of the Properties panel of the ribbon Geometry Properties One of the most common categories in the Properties palette is Geometry. Although most objects have a Geometry category, the properties within the category vary depending on the type of object. Typically, three properties allow you to change the absolute coordinates for the object by specifying the X, Y, and Z coordinates. When you select one of these properties, a pick button is displayed. The button allows you to pick a point in the drawing for the new location. Text Properties The Text category, which is displayed when single-line or multiline text is selected, contains properties such as text style and justification. These properties can be adjusted using traditional techniques, such as reentering the text editor to modify the text. However, the Properties palette provides a convenient way to modify a variety of text properties without reentering the Matching Properties The MATCHPROP tool allows you to copy properties quickly from one object to one or more other objects. The Matchprop tool may be accessed by selecting the matchprop icon on the properties tool bar on the home ribbon, or by typing Matchprop, Painter or MA at the command prompt MatchProp Tool When you first access the MATCHPROP tool, AutoCAD prompts you for the source object. After you select the source object, AutoCAD displays the properties it will paint to the destination object. The next prompt allows you to pick the objects you want to receive the properties of the source object. MatchProp Tool To change the properties to be painted, select the active Settings option before picking the destination object(s). The Property Settings dialog box appears, showing the types of properties that can be painted. The Basic Properties area lists the general properties of the selected object. The Special Properties area contains check boxes that allow you to paint over a variety of additional properties related to object styles. Properties are replaced in the destination object if the corresponding Property Settings dialog box check boxes are active. 7

8 Editing between Drawings The advantages of using AutoCAD include the ability to edit in more than one drawing at a time and to edit between open drawings. For example, you can copy objects from one drawing to another drawing. You can also refer to a drawing to obtain information, such as a distance, while working in a different drawing. Copying and Pasting From Drawing to Drawing The shortcut menu has two options that allow you to copy to the Windows Clipboard. The Copy option copies selected objects from AutoCAD onto the Windows Clipboard to be used in another application or AutoCAD drawing. The Copy with Base Point option also copies the selected objects to the Clipboard, but it allows you to specify a base point to position the copied object when it is pasted. When you use this option, AutoCAD prompts you to select a base point. Select a logical base point, such as a corner or center point of the object. After you select one of the copy options, make the second drawing active by picking in it or by using the [Tab] + [Ctrl] key combination. Right-click to display the shortcut menu shown and select paste, paste as block, or p aste to original coordinates. Copying and Pasting Paste as Block Option The Paste as Block option joins all objects on the Clipboard when they are pasted into the drawing. The pasted objects act like a block in that they are single objects grouped together to form one object Blocks may be Exploded to disassociate the components Explode Tool To access the explode tool select the explode tool from the modify tool panel on the home ribbon or type Explode at the command prompt. Lab Assignment P14-4, P14-5, P14-6 8

9 Learning Objectives Chapter 15 Polylines Use the PLINE tool to draw straight and curved polylines. Use the REVCLOUD tool to mark up drawings. Edit existing polylines with the PEDIT tool. Use the EXPLODE tool to change polylines into individual line and arc segments. Create a polyline boundary. Polyline Polylines provide more flexibility than lines. They are typically used to create objects composed of arcs and straight lines of varying thickness. Polylines are drawn using the PLINE tool. When using the default polyline settings, the process of drawing polyline segments is identical to the process of creating line segments using the LINE tool. Polyline Tool The PLINE tool also offers additional options not found with the LINE tool. It can be used to draw a variety of special shapes, including thick and tapered lines and polyline arcs. The polyline tool is accessed by selecting the pline icon or by typing PLINE, or PL at the command prompt. Pline Tool The default polyline settings create a polyline with a constant width of 0. A polyline drawn using a constant width of 0 is similar to a standard line and will accept the lineweight applied to the layer on which it is drawn. If a width of 0 is acceptable, simply select the first point and then the endpoint of the line segment. As you draw additional line segments, the endpoint of the first line segment automatically becomes the starting point of the next line segment. Pline Tool Width Option To change the width of a line segment, access the PLINE tool, select the first point, and then enter W to access the Width option. With the width option is selected, you will be prompted to specify the starting and ending widths of the line. To exit the pline tool, press [Enter], [Esc] or the space bar or right-click and select the Enter menu option. 9

10 Pline Width Option The starting width value becomes the default setting for the ending width. Therefore, to draw a line segment with constant width, right-click or press [Enter] or the space bar at the second prompt. After the widths are specified, the rubberband line from the first point reflects the width settings. Pline Width Option Using a starting and/or ending width value other than 0 overrides the lineweight applied to the layer on which the polyline is drawn. To create a tapered line segment, enter different values for the starting and ending widths. One special use of a tapered polyline is the creation of arrowheads. To draw an arrowhead, use the Width option of the PLINE tool, specify 0 as the starting width, and then use any desired ending width. Pline Half Width Option The Halfwidth option of the PLINE tool allows you to specify the width of the polyline from the center to one side, as opposed to the total width of the polyline defined using the Halfwidth option. After accessing the PLINE tool, pick the first point of the polyline, and then enter H to access the Halfwidth option. Pline Length Option The Length option of the PLINE tool allows you to draw a polyline parallel to the previous polyline or line. After drawing a polyline, reissue the PLINE tool and pick a start point. Enter the Length option and give the desired length. The second polyline is drawn parallel to the previous polyline with the length you specified Pline Undo Option To remove the last segment of a polyline without leaving the PLINE tool, use the Undo option. This removes the previously drawn segment and allows you to You can use the Undo option repeatedly to continue deleting polyline segments until the entire object is gon Polyline Arc Option The Arc option of the PLINE tool is similar to the ARC tool, except that the width and halfwidth options of the PLINE tool can be used to set an arc width. Enter after A to create an arc segment when in the polyline tool. The arc width can range from 0 to the radius of the arc. A polyline arc can also be drawn with different starting and ending widths using the Width option. 10

11 Polyline Arc Options The polyline arc suboptions are very similar to the ARC tool options. A polyline li arc can also be drawn with different starting and ending widths using the Width option. Polyline Arc Option By default, a polyline arc continued from a previous line or polyline is tangent to the last object drawn. The center of the arc is determined automatically, but you can pick a new center. You can also specify settings with one of the Arc suboptions of the PLINE tool, including: Angle, CEnter, Direction, Radius, Second pt (second point), and CLose. Polyline Arc Sub-options- Included Angle The Angle suboption allows the Autocad user to specify an included angle for a polyline arc. Polyline Arc Sub-options- Included Angle The angle value is based on the number of degrees in a circle. The values 0 and 360 cannot be entered. A negative value draws the arc in a clockwise direction. Polyline- Arc Sub-options -Specifying a New Center Point When a polyline arc is drawn as a continuation of a polyline segment, the center point of the arc is calculated automatically. If the polyline arc does not continue from another object or if the center point AutoCAD calculated is not suitable, use the Center suboption to specify a new center point for the arc. Polyline- Arc Sub-options -Specifying a New Center Point The Center sub-option is accessed by entering CE once you have accessed the pline arc option. 11

12 Polyline- Arc Sub-options -Specifying a New Center Point When you access the CEnter suboption and pick the center point, the radius of the arc is set as the distance from the center point to the start point. You can then choose from three methods to complete the polyline arc: pick the endpoint of the arc, use the Angle option to specify the included angle, or use the Length option to specify the chord length of the arc. Polyline- Arc Sub-options Direction Sub-option The Direction sub-option alters the bearing of the arc. By default, a polyline arc is created tangent to the last polyline, arc, or line drawn. The Direction sub-option is used to change this setting. To access the Direction sub-option, type and enter D when the pline arc suboption is active. Polyline- Arc Sub-options Direction Sub-option After selecting the Direction sub-option of the PLINE Arc option, specify the tangent direction for the start point of the arc. You may enter a numeric angle value, or you can pick a point to define the angle relative to the start point. Polyline Arc Sub-options Radius Enter R and then enter value for radius. Close- Enter C to close the polyline and return to the start point Three point arc Enter S to access the second point sub-option, you will then be prompted to select a second an then a third point. Revision Cloud Revision clouds are typically used by people who review drawings and mark notes and changes. The revision cloud points the drafter to a specific portion of the drawing that may need to be edited. Revision clouds are drawn using the REVCLOUD tool. Revision Cloud A revision cloud is a polyline of sequential arcs forming a cloud- shaped object. To access the Revcloud tool select the rev cloud icon from the expanded draw tool bar or type REVCLOUD at the command prompt 12

13 Revision Cloud Tool To begin drawing the revision cloud, pick a start point in the drawing. After you pick the start point, the prompt tells you to guide the crosshairs along the cloud path. Move the crosshairs around the objects to be enclosed until you come close to the start point. AutoCAD then closes the cloud automatically and exits the tool. Revision Cloud Arc Length Option The size of the arcs in a revision cloud can be set by entering the Arc length option of the REVCLOUD tool. This value measures the length of an arc from its start point to its end point. You can change the arc length to any desired value. Access the Arc length option before picking the start point for the revision cloud. Revision Cloud Arc Length Option Enter A to access the arc length option after activating the revcloud tool. AutoCAD prompts for the minimum arc length and then for the maximum arc length. Enter the minimum and maximum arc lengths to return to the Specify start point: prompt. Specifying different minimum and maximum values causes the revision cloud to have an uneven, hand-drawn look. Revision Cloud Style Option The style option of the REVCLOUD tool offers two style choices: Normal and Calligraphy. The default style is Normal, in which the arcs are a consistent width. Enter S after accessing the revcloud tool to change the style. In the Calligraphy style, the start and end widths of the individual arcs are different, creating a more stylish revision cloud. Converting Objects into Revision Clouds Circles, closed polylines, ellipses, polygons, and rectangles can be converted to revision clouds by selecting the Object option, (Enter O ) of the REVCLOUD tool. Access the Object option instead of picking the start point for the revision cloud. Then pick the object to convert to a revision cloud. Enter the No option at the Reverse direction: prompt, or use the Yes option to reverse the direction of the cloud arcs. Wipeout Tool The WIPEOUT tool is used to clear a portion of the drawing, without erasing objects. To access the wipeout tool, select the wipeout icon from the expanded Draw menu or type Wipeout at the command prompt. 13

14 Wipeout Tool A wipeout can be created by picking points or converting an existing closed polyline object into a wipeout. You also have the option of turning the display of the frame, or boundary, on or off. If text is required in addition to the wipeout, however, it is more convenient to use the Background mask function of the MTEXT tool. Editing Polyline Objects AutoCAD combines all polyline segments constructed during a single PLINE tool operation to form a single object. The entire polyline object is edited using the PEDIT tool. To access the polyline edit tool select the pedit icon or type PEDIT or PE at the command prompt Pedit Tool There is no default option for the PEDIT tool you must select one of the options. When you pick a wide polyline to edit, you must select the edge of a polyline segment rather than the center. Pedit Tool Multiple Option Enter M after accessing the pedit tool to enter multiple mode. If you want to edit more than one polyline, activate the Multiple option before selecting. Pedit Tool If the object you select is a line or arc object, AutoCAD issues a prompt that gives you the option to turn it into a polyline. If you select the Yes option, the object is converted to a polyline and the PEDIT tool continues normally. Pedit Tool You can also access the PEDIT tool by selecting a polyline, right clicking, and choosing the Polyline li Edit shortcut t menu option. 14

15 PEDIT Open and Close Options The Open and Close options of the PEDIT tool allow you to close an open polyline or open a closed polyline. The Open option is only available if the polyline was closed using the Close option of the PLINE tool. If you select an open polyline, the Close option is displayed instead of the Open option. PEDIT Tool Join Option Connected polylines, lines, and arcs can be joined to create a single polyline using the Join option of the PEDIT tool. The Join option works only if the polyline and other existing objects meet exactly. They cannot cross, nor can there be any spaces or breaks between the objects. Enter J while the pedit tool is active to select the join optiion PEDIT Tool Join Option Select each object to be joined or group the objects with one of the selection set options. The original polyline can be included in the selection set, but it does not need to be. If you select lines and arcs to join, AutoCAD automatically converts these objects to polylines. PEDIT Tool Width Option The Width option of the PEDIT tool allows you to assign a new width to a polyline. The width of the original polyline can be constant, or it can vary. All segments will be changed, however, to the constant width you specify PEDIT Tool Edit Vertex The Edit vertex option of the PEDIT tool is used to edit a polyline vertex and a point of tangency. When you enter the Edit vertex option, an X marker appears onscreen at the first polyline vertex or point of tangency. The Edit vertex option contains several suboptions PEDIT Tool Edit Vertex If you edit the vertices of a polyline and nothing appears to happen, use the Regen option to regenerate the polyline. Select the exit option to return to the PEDIT tool prompt. 15

16 PEDIT Tool Edit Vertex Only the point identified by the X marker is affected by editing functions. Options include Next, Previous, Regen, Break, Insert and Exit PEDIT Edit Vertex PEDIT Edit Vertex Break Option You can break a polyline into two separate polylines with the Break option of the PEDIT Edit vertex option. Enter the Edit vertex option, use the Next or Previous option to move the X marker to the first vertex where the polyline is to be broken, and then enter the Break option. PEDIT Edit Vertex Break Option A marker is placed at the first break point. After moving to the second vertex of the break, enter the Go option. The Go option instructs AutoCAD to remove the portion of the polyline between the two points. You can also break the polyline without removing a segment by specifying Go without moving to a second vertex. PEDIT Edit Vertex Insert Option A new vertex can be added to a polyline using the Insert editing option. The new vertex can be inserted on an existing polyline li segment, but does not need to be. First, use the Next or Previous option to locate the vertex next to where you want the new vertex. Select the Insert option and pick the new vertex location. PEDIT Edit Vertex Insert Option 16

17 PEDIT Edit Vertex Move Option PEDIT Edit Vertex Move Option The Move vertex editing option enables you to move a polyline vertex to a new location. The X marker must first be placed on the vertex you want to move. Enter the Move option, by typing M, and specify the new vertex location PEDIT WIDTH OPTION The Width vertex editing option is used to change the starting and ending widths of an individual polyline segment. To change a segment width, move the X marker to the beginning vertex of the segment to be altered. Enter the Width option and specify the new width. The default starting width value is the current width of the segment to be changed. PEDIT- Straighten Option The Straighten vertex editing option allows you to straighten polyline segments or arcs between two points. Position the X marker at one end of the polyline segment to be straightened and enter the Straighten option. PEDIT- Straighten Option The Straighten option has four suboptions: Next, Previous, Go, and Exit. Use the Next and Previous options to position the X marker at the end of the segment to be straightened. Then enter the Go option to straighten the polyline segment. Fitting a Curve to a Polyline In some situations, you may need to convert a polyline into a series of smooth curves. One example of this is a graph. A graph may show a series of plotted points as a smooth curve rather than straight segments. This process is called curve fitting and is accomplished using the Fit option and the Tangent vertex editing option of the PEDIT tool. 17

18 Fitting a Curve to a Polyline The Fit option creates a fit curve by constructing pairs of arcs that pass through control points. You can specify the control points, or you can use the vertices of the polyline. Fitting a Curve to a Polyline The Tangent vertex editing option is used to edit tangent directions. After entering the PEDIT tool and the Edit vertex option, move the X marker to the first vertex to be changed. Enter the Tangent option and specify a tangent direction in degrees or pick a point in the expected direction. An arrow placed at the vertex then indicates the direction you chose. Fitting a Curve to a Polyline Move the marker to each vertex you want to change, entering the Tangent option for each vertex and selecting a tangent direction. Lab Assignment P15-6, P15-13 When the tangent directions have been specified for all vertices to be changed, enter the Fit option of the PEDIT tool to create the curve. 18