Creating Objects. In This Chapter

Transcription

1 Creating Objects In This Chapter 6 With the AutoCAD drawing tools, you can create a range of objects, from simple lines and circles to spline curves, ellipses, and hatched areas that change when their boundaries change. In general, you draw objects by specifying points with the pointing device or by entering coordinate values on the command line. For information about drawing three-dimensional objects, see chapter 7, Working in Three-Dimensional Drawing line objects, polylines, multilines, polygons, and freehand sketches Drawing curved objects such as circles, arcs, ellipses, and spline curves Changing the order of objects in a drawing Creating solid-filled areas, regions, and hatched areas Understanding named, custom, and proxy objects Using wild-card characters Space. 3

2 Drawing Lines The line is the basic object in AutoCAD. You can create a variety of lines: single lines, multiple line segments with and without arcs, multiple parallel lines, and freehand sketch lines. In general, you draw lines by specifying coordinate points, properties such as linetype or color, and measurements such as angles. See Specifying Coordinates on page 0. The default linetype is CONTINUOUS, an unbroken line, but various linetypes are available that use dots and dashes. See Working with Linetypes on page 333. Drawing Line Objects A line can be one segment or a series of connected segments, but each segment is a separate line object. Use lines if you want to edit individual segments. If you need to draw a series of line segments as a single object, use a polyline (see Drawing Polylines on page 4). You can close a sequence of lines so that the first and last segments join to form a closed loop. To draw a line From the Draw menu, choose Line. Specify the start point (). 3 Specify the endpoint (). 4 Specify the endpoints of the next segments (3, 4, 5, 6). 5 Press ENTER to complete the line. To undo the previous line segment during the LINE command, enter u. You can start a new line at the endpoint of the last line drawn by starting LINE again and pressing ENTER at the Start Point prompt. next point start point last point Command line LINE Related PLINE draws polyline line and arc segments that form a single object. MLINE draws multiple parallel lines. OFFSET creates copies of lines offset at a specified distance to one side or through a point. LINETYPE sets the current linetype. Drawing Polylines A polyline is a connected sequence of line or arc segments created as a single object. Use polylines if you want to edit all segments at once, although you can also edit them singly. You can set the width of individual segments, make segments taper, and close the polyline. When you draw arc segments, the 4 Chapter 6 Creating Objects

3 first point of the arc is the endpoint of the previous segment. You can specify the angle, center point, direction, or radius of the arc. You can also complete the arc by specifying a second point and an endpoint. pipe symbol Polylines with arc segments differing widths an insulated wall To draw a polyline with straight segments From the Draw menu, choose Polyline. Specify the first point of the polyline. 3 Specify the endpoint of each polyline segment. 4 Enter c (Close) to close the polyline, or press ENTER to end the command. Command line PLINE endpoint of arc final segment 3 Related LINE creates single or multiple line segments that are separate objects. MLINE creates multiple parallel lines. In the next example, you draw a polyline line segment, continue with an arc segment, and then draw another line segment in a tangential direction. To draw a line and arc combination polyline First draw the line segment. From the Draw menu, choose Polyline. Specify the start point of the line segment (). 3 Specify the endpoint of the line segment (). 4 Enter a to switch to Arc mode. 5 Specify the endpoint of the arc (3). 6 Enter l to return to Line mode. 7 Enter the distance and angle of the line in relation to the endpoint of the arc. You can enter these relative values in the 8 Press ENTER to end the polyline. Drawing Lines 5

4 After you ve created a polyline, you can edit it with PEDIT or use EXPLODE to convert it to individual line and arc segments. When you explode a wide polyline, the line width reverts to 0 and the resulting line segments are positioned along the center of what was the wide polyline. Drawing Multilines Multilines consist of between and 6 parallel lines, called elements. You position the elements by specifying the desired offset of each element from the origin of the multiline. You can create and save multiline styles or use the default style, which has two elements. You can set the color and linetype of each element and display or hide the joints of the multiline. Joints are lines that appear at each vertex. There are several types of end caps you can give the multiline, for example, lines or arcs. five elements ten elements end caps three elements Examples of multilines To draw a multiline From the Draw menu, choose Multiline. At the Command prompt, enter st to select a style. 3 To list available styles, enter the style name or enter?. 4 To justify the multiline, enter j and choose top, zero, or bottom justification. 5 To change the scale of the multiline, enter s and enter a new scale. Now draw the multiline. 6 Specify the starting point. 7 Specify the second point. 8 Specify the third point. 9 Specify the fourth point or enter c to close the multiline, or press ENTER. Command line MLINE Creating Multiline Styles You can create named styles for multilines to control the number of elements and the properties of each element. The style also controls the background fill and the end cap. See Editing Multilines on page Chapter 6 Creating Objects

5 To create a multiline style From the Format menu, choose Multiline Style. loads style from external file saves style to external file In the Multiline Styles dialog box, enter a name and description for the style. Descriptions are optional and can be up to 55 characters, including spaces. 3 To create a multiline style, choose Add. 4 To add elements to the style or to modify existing elements, choose Element Properties. 5 In the Element Properties dialog box, highlight the element in the list, and then make changes to Offset, Color, and Linetype. 6 To add an element, choose Add, and then make changes to Offset, Color, and Linetype. Choose OK. The offset defines the 0,0 origin of the multiline relative to which other elements are drawn. An element does not have to be drawn at the origin. 7 To set multiline properties, choose Multiline Properties in the Multiline Styles dialog box. 8 In the Multiline Properties dialog box, make any changes and choose OK. Properties include the display of segment joints and the type of start and end caps with their angles and fill color. 9 Choose Save to save the style to an external multiline style file (the default is acad.mln). You can save multiline styles to the same file. If you create more than one multiline style, save the current style before creating a new one or you lose the changes to the first style. Drawing Lines 7

6 You can add up to 6 elements to a multiline style. If you create or modify an element so that it has a negative offset, it appears below the origin in the image tile of the Multiline Styles dialog box. To specify the properties of the entire multiline From the Format menu, choose Multiline Style. In the Multiline Styles dialog box, choose Multiline Properties. toggles display of multiline joints controls display of end caps controls background fill 3 In the Multiline Properties dialog box, select Display Joints to display a line at the vertices of the multiline. 4 Under Caps, select a line or an arc for each end of the multiline, and enter an angle. Lines cross the end of the whole multiline, and outer arcs join the ends of the outermost elements. Inner arcs connect pairs of elements, leaving the centerline unconnected if there is an odd number of elements. For example, if there are six elements, inner arcs connect elements and 5 and elements 3 and 4. If there are seven elements, inner arcs connect elements and 6 and elements 3 and 5; element 4 is left unconnected. line cap outer arc inner arcs with six elements inner arcs with seven elements 8 Chapter 6 Creating Objects

7 5 Under Fill, select On to display a background color. This color is not displayed in the image tile of the Multiline Styles dialog box. 6 Choose Color. 7 In the Select Color dialog box, select the background fill color and choose OK. 8 In the Multiline Properties dialog box, choose OK to return to the Multiline Styles dialog box. Next, save the multiline style. To save a multiline style name In the Multiline Styles dialog box under Name, enter a name and a description for the style. Descriptions are optional and may have up to 55 characters, including spaces. To add the newly created multiline style to the drawing and set it as current, choose Add. 3 To save the style to an external MLN file, choose Save. 4 Choose OK. Command line MLSTYLE System variables CMLSTYLE stores the name of the current multiline style. Related The OFFSET command creates new objects at a specified offset from a selected object or through a specified point. Using Existing Multiline Styles When you start drawing a multiline, you can use the default style, which has two elements, or specify a style you created previously. The default style is the multiline style last used, or the STANDARD style if MLINE hasn t been used. You can also change the justification and scale of the multiline before you draw it. Justification determines whether the multiline is drawn below or above the cursor, or with its origin centered on the cursor. The default is below (top justification). Scale controls the overall width of the multiline using the current units. Multiline scale does not affect linetype scale. If you are changing the multiline scale, you might need to make equivalent changes to linetype scale to prevent dots or dashes from being disproportionately sized. Drawing Lines 9

8 Drawing Polygons Polygons are closed polylines with between 3 and,04 equal-length sides. You draw a polygon by inscribing it in, or circumscribing it about, an imaginary circle or by specifying the endpoints of one of the edges of the polygon. Because polygons always have equal-length sides, they provide a simple way to draw squares and equilateral triangles. The following illustrations show polygons drawn using the three methods. In the first two illustrations, point is the center of the polygon and point defines the radius length, which is being specified with the pointing device. Three methods for drawing polygons edge start point inscribed circumscribed edge edge endpoint Drawing Inscribed Polygons Use inscribed polygons when you want to specify the distance between the center of the polygon and each vertex. This distance is the radius of the circle within which the polygon is inscribed. In this example, you draw an inscribed square, the default polygon. To draw an inscribed square From the Draw menu, choose Polygon. Enter 4 to specify four sides for the polygon. 3 Specify the center point for the polygon (). 4 Enter i (Inscribed in Circle). 5 Specify the radius (). Command line POLYGON Related RECTANG creates polyline rectangles. 30 Chapter 6 Creating Objects

9 Drawing Circumscribed Polygons Use circumscribed polygons when you want to specify the distance between the center of the polygon and the midpoint of each side. This distance is the radius of the circle the polygon circumscribes. To draw a circumscribed hexagon From the Draw menu, choose Polygon. Enter 6 for the number of sides. 3 Specify the center of the polygon (). 4 Enter c (Circumscribed about Circle). 5 Specify the radius length (). After you ve created a polygon, you can edit it with PEDIT or convert it to individual line segments with EXPLODE. Sketching Freehand You can use the SKETCH command to draw freehand sketches. Freehand sketches comprise many line segments. Each line segment can be a separate object or a polyline. You set the minimum length or increment of the segments. Sketching is useful for creating irregular boundaries or for tracing with a digitizer. Small line segments allow for greater accuracy, but they can greatly increase the drawing file size. For this reason, use this tool sparingly. Before sketching, check the CELTYPE system variable to make sure the current linetype is BYLAYER. If you use a linetype with dots or dashes and set the sketch line segment shorter than the spaces or dashes, you won t see the spaces or dashes. To sketch, use the pointing device like a pen, clicking to put the pen down on the screen to draw and clicking again to lift it up and stop drawing. sketch lines Freehand sketches Drawing Lines 3

10 To sketch and record freehand lines At the Command prompt, enter sketch. At the Record Increment prompt, enter the minimum line segment length. 3 Click the start point to put the pen down. When you move the pointing device, AutoCAD draws temporary freehand line segments of the length you specified. SKETCH doesn t accept coordinate input. During the command, freehand lines are displayed in a different color. 4 Click the endpoint to lift the pen up so that you can move the cursor around the screen without drawing. Click a new start point to resume drawing from the new cursor position. 5 Enter r at any time to record (save) in the database the line you re drawing and those already drawn. If the pen is down, you can continue drawing after recording. If the pen is up, click to resume drawing. The freehand line starts from wherever the cursor is when you click. 6 Press ENTER to complete the sketch and record all unrecorded lines. If you want to use Snap or Ortho mode while sketching, you must use the keyboard toggles (F8 for Ortho, F9 for Snap). The status bar toggles have no effect. The Snap setting overrides the record increment if Snap is the larger setting. If Snap is smaller, the record increment takes precedence. System variables SKETCHINC sets the size of freehand line segments. SKPOLY draws the freehand line as a polyline if it is not set to 0. Erasing Freehand Lines You erase freehand lines by using the Erase option of the SKETCH command. In Erase mode, wherever the cursor intersects the freehand line, everything from the intersection to the end of the line is erased. Once you record freehand lines, you can t edit them or erase them with the Erase option of SKETCH. Use the ERASE command after you finish sketching. To erase freehand lines With the pen up or down, enter e (Erase). If the pen was down, it moves up. Move the cursor to the end of the line you drew last and then move it back as far along the line as you want to erase. 3 To end the erasure and return to the SKETCH Command prompt, enter p. To undo the erasure, enter e. If you want to change the current viewport while sketching, make sure the pen is up, all lines entered so far have been recorded, and Tablet mode is off. 3 Chapter 6 Creating Objects

11 Sketching in Tablet Mode You use Tablet mode with a digitizer. Sketching in Tablet mode is useful for such things as tracing map outlines from paper directly into an AutoCAD drawing. You can t turn off Tablet mode while sketching. When Tablet mode is on, you can configure AutoCAD to map the paper drawing s coordinate system directly into the AutoCAD world coordinate system. Thus, there is a direct correlation between the coordinates where screen crosshairs appear, the coordinates on the tablet, and the coordinates in the original paper drawing. After configuring AutoCAD to match the coordinates of the paper drawing, you may find that the area shown on the screen is not the area you need. To avoid this problem, use ZOOM to display the entire work area before you start to sketch. With some digitizers you can t select the menus while Tablet mode is on. See your digitizer documentation for details. Maintaining Sketching Accuracy To ensure accuracy on a slow computer, set the record increment value to a negative value. SKETCH uses this value as if it were positive but tests every point received from the pointer against twice the record increment. If the point is more than two record increments away, your computer beeps as a warning that you should slow down to avoid losing accuracy. For example, if the record increment is, you should move the cursor in increments of no more than. Using this method does not slow down the tracing speed. Drawing Curved Objects You can create a variety of curved objects with AutoCAD, including circles, arcs, ellipses, spline curves, and donuts. Drawing Circles You can create circles in several ways. The default method is to specify the center and radius. You can also specify the center and diameter or define the diameter alone with two points. You can define the circle s circumference with three points. You can also create the circle tangent to three existing objects or create it tangent to two objects and specify a radius. In the following illustrations, the darker circles are the ones being drawn. Drawing Curved Objects 33

12 center radius 3 radius tangent objects center, radius two points defining diameter three points defining circumference tangent tangent, radius Four methods of drawing circles To draw a circle by specifying a center point and radius radius center From the Draw menu, choose Circle Center, Radius. Specify the center point. 3 Specify the radius. Command line CIRCLE To create a circle that is tangent to two objects, specify a tangent point on each of the objects and the radius of the circle. The tangent point can be any point on the object. In the following illustrations, the darker circle is the one being drawn, and the tangent points are points () and (). radius of new circle = radius of new circle = radius of new circle = 4 Circles created tangent to two objects To create a circle tangent to existing objects From the Draw menu, choose Circle Tan, Tan, Radius. You are now in Tangent snap mode. Select the first object to draw the circle tangent to. 34 Chapter 6 Creating Objects

13 3 Select the second object to draw the circle tangent to. 4 Specify the radius of the circle. To create a circle tangent at two or three points, set OSNAP to Tangent and use the two-point or three-point method to create the circle (see Snapping to Points on Objects on page 67). Drawing Arcs You can create arcs in many ways. The default method is to specify three points a start point, a second point on the arc, and an endpoint. You can also specify the included angle, radius, direction, and chord length of arcs. The chord of an arc is a straight line between the endpoints. By default, AutoCAD draws arcs counterclockwise. In the following example, the start point of the arc snaps to the endpoint of a line. The second point of the arc snaps to the middle circle. 3 3 start (), center, (), end (3) center (), start (), end (3) To draw an arc by specifying three points endpoint of line 3 arc drawn using default 3-point method From the Draw menu, choose Arc Start, Center, End. Specify the start point () by entering endp and selecting the line. The arc snaps to the endpoint of the line. 3 Specify the second point () by entering cen and selecting the existing arc to define the center of the arc. 4 Specify the endpoint of the arc (3). Command line ARC Related ELLIPSE creates elliptical arcs. PLINE creates arc segments within D polylines. In the following illustrations, the center of an existing circle is used as the center of the arc. Once you specify the center and start points of the arc, you complete the arc by specifying the chord length. The distances shown in these illustrations from one endpoint to the cursor are chord lengths. Drawing Curved Objects 35

14 chord length chord length start, center, length center, start, length To draw an arc using a start point, a center point, and a chord length From the Draw menu, choose Arc Start, Center, Length. Specify a start point (). 3 Specify the center point (). 4 Specify the chord length. included angle Use the Start, Center, Angle or Center, Start, Angle method when you have a start point and a center point you can snap to. The angle determines the endpoint of the arc. Use the Start, End, Angle method when you have both endpoints but no center point to snap to. start, center, angle center, start, angle start, end, angle The following illustration on the left shows an arc drawn by specifying a start point, endpoint, and radius. You can specify the radius by entering a length or by moving the cursor away from the endpoint to specify a distance. radius start, end, radius start, end, direction direction 36 Chapter 6 Creating Objects

15 The previous illustration on the right shows an arc drawn with the pointing device by specifying a start point and endpoint and a direction of the tangent. Moving the cursor up from the start point and endpoint draws the arc concave to the object, as shown here. Moving the cursor down would draw the arc convex to the object. You can start a line at the endpoint of the last drawn arc by starting LINE and pressing ENTER at the Start Point prompt. The arc s endpoint defines the start point and the tangential direction of the new line. You need to specify the length. arc endpoint resulting line Drawing Spline Curves A spline is a smooth curve passing through a given set of points. AutoCAD uses a particular type of spline known as a nonuniform rational B-spline (NURBS) curve. A NURBS curve produces a smooth curve between control points. Splines are useful for creating irregular-shaped curves, for example, drawing contour lines for geographic information system (GIS) applications or automobile design. splines AutoCAD creates true splines which are NURBS curves with the SPLINE command. You can also create linear approximations of splines by smoothing polylines with PEDIT. You can convert D and 3D smoothed polylines to splines with SPLINE. Creating true spline curves rather than editing polylines to approximate splines has three advantages: Spline curves can be created by interpolating the spline through a set of points that lie on the desired path of the curve. This method creates curved boundaries far more accurately than polylines for both D drafting and 3D modeling. Drawing Curved Objects 37

16 Splines can be edited easily either with the SPLINEDIT command or with grips, and the spline definition is maintained. This definition is lost with PEDIT-smoothed polylines. See Editing Splines on page 98. A drawing containing splines uses less disk space and memory than a drawing with smoothed polylines. You create splines by specifying points. You can close the spline so the start point and endpoint are coincident and tangent. You can also change the spline-fitting tolerance while drawing the spline to see how closely the spline fits the set of specified fit points. The lower the tolerance, the more closely the spline fits the points. At zero tolerance, the spline passes through the points. To create a spline by specifying points From the Draw menu, choose Spline. Specify the spline s start point (). 3 Specify points ( through 5) to create the spline and press ENTER Specify the start and end tangents (6 and 7). 7 6 The following illustration shows the result when you use the same points but different start and end tangents Chapter 6 Creating Objects

17 The following spline is drawn using the same points but a higher tolerance and different start and end tangents Command line SPLINE Related SPLINEDIT edits a spline object. PLINE draws polyline line and arc segments that form a single object. PEDIT can modify a polyline into an approximation of a spline. Drawing Ellipses You can create full ellipses and elliptical arcs, both of which are exact mathematical representations of ellipses. The default method of drawing an ellipse is to specify the endpoints of the first axis and the distance, which is half the length of the second axis. The longer axis of an ellipse is called the major axis, and the shorter one is the minor axis. The order in which you define the axes does not matter. distance distance midpoint of first axis major axis endpoints of first axis minor axis In the following procedure, you draw an ellipse using the default method and the pointing device. Here, the first axis is the major axis, and the second is the minor. The distance increases as you drag the pointing device away from the midpoint. Drawing Curved Objects 39

18 To draw a true ellipse using endpoints and distance From the Draw menu, choose Ellipse Axis, End. Specify the first endpoint of the first axis (). 3 Specify the second endpoint of the first axis (). 4 Drag the pointing device away from the midpoint (3) of the first axis and click to specify the distance. Command line ELLIPSE 3 cursor dragged to specify distance You can provide a rotation angle instead of a distance or draw the ellipse based on a center point, an endpoint of one axis, and half the length of the other axis. 3 3 first axis as major axis first axis as minor axis 3 Ellipses created by specifying axis endpoints and distance In the illustrations above, points and are the endpoints of the first axis, and point 3 defines the distance (half the length) of the second axis. The ellipse at the left is drawn by specifying the center () and two axes. The endpoint of the first axis is at point, and point 3 defines half the length of the second axis. Drawing Elliptical Arcs The default method of drawing elliptical arcs uses the first axis endpoints and the second axis distance, as for full ellipses. You then specify start and end angles. The apex of the angle is the center of the ellipse, and the major axis is defined as 0 degrees. The start angle defines the start point of the elliptical arc. The end angle defines the endpoint, and the arc is drawn between these points in the direction set by the ANGDIR system variable. If ANGDIR is 0, the angles are measured in a counterclockwise direction. If ANGDIR is, they are measured in a clockwise direction. 40 Chapter 6 Creating Objects

19 5 4 3 If the start and end angles are the same, you create a full ellipse. You can also specify a start angle and an included angle. The included angle is measured relative to the start point instead of from 0 degrees. In the following procedure, start and end angles are measured from point, the first endpoint of the first axis, ANGDIR is set to 0, so the angles are measured counterclockwise from point. The start angle (4) is 30-degrees and the end angle (5) is 50-degrees. To draw an elliptical arc using start and end angles From the Draw menu, choose Ellipse Arc. Specify endpoints for the first axis ( and ). 3 Specify the distance of the second axis (3). 4 Specify a start angle (4). 5 Specify an end angle (5). isometric circles Related ARC creates arcs. PLINE creates arc segments within polylines. Drawing Isometric Circles If you are drawing on isometric planes to simulate three dimensions, you can use ellipses to represent circles viewed from an oblique angle. First you need to turn on an isometric plane (see Setting Snap and Grid to Isometric Mode on page 66). To draw an isometric circle Turn on the Isometric snap and grid. From the Draw menu, choose Ellipse Axis, End. 3 Enter i (Isocircle). 4 Specify the center of the circle (). 5 Specify the radius or diameter of the circle (). Drawing Donuts Drawing donuts is a quick way to create filled rings or solid-filled circles. Donuts are actually closed polylines that have width. To create a donut, specify its inside and outside diameters and its center. You can continue Drawing Curved Objects 4

20 creating multiple copies with the same diameter by specifying different centers until you press ENTER to end the command. To create solid-filled circles, specify an inside diameter of 0. donuts donut filled rings solid-filled circles 3 Donuts created as filled rings and solid-filled circles To draw a donut From the Draw menu, choose Donut. Specify the inside diameter (). 3 Specify the outside diameter (). 4 Specify the center of the donut (3). 5 Specify the center point for another donut or press ENTER to end the command. Command line DONUT System variables DONUTID stores the inside diameter value of a donut; DONUTOD stores the outside diameter value. FILLMODE controls the display of donuts and other wide polylines. Related PEDIT edits donuts. EXPLODE converts a donut to two arcs. If you explode a donut, its line width reverts to 0. Creating Point Objects Point objects can be useful, for example, as node or reference points that you can snap to and offset objects from. You can set the style of the point and its size relative to the screen or in absolute units. 4 Chapter 6 Creating Objects

21 To set point style and size From the Format menu, choose Point Style. sets style sets size In the Point Style dialog box, select a point style. 3 Under Point Size, specify a size. 4 Choose OK. Command line DDPTYPE To create a point marker From the Draw menu, choose Point Single Point. Specify the point location. Command line System variables size. POINT PDMODE sets different point styles. PDSIZE controls point Changing the Drawing Order of Objects By default, objects are drawn in the order they are created. DRAWORDER changes the display order of objects, moving one in front of another, for example. Ordering ensures proper display and plotting output when two or more objects overlay one another. An example of when ordering may be necessary is when a raster image is drawn over existing objects, obscuring them from view. Changing the Drawing Order of Objects 43

22 To change the drawing order of an object Select the objects whose drawing order you want to change. From the Tools menu, choose Display Order. 3 Select Bring to Front or Send to Back to indicate the drawing order of the selected objects. Or, select Bring Above Object or Send Under Object to select the object you want to move above or below. Command line DRAWORDER Regenerating the Drawing Order When you open a drawing previously saved with a specified drawing order, the display is regenerated based on the original order in which the objects were created. To display objects in the DRAWORDER command order, use the REGEN command. REGEN regenerates the display in the current viewport, but because it also regenerates the entire drawing, the screen coordinates for all objects are also regenerated. The REDRAW command refreshes the display in the current viewport but does not recalculate the coordinates for all objects. REDRAW takes much less time than REGEN. For more information about REDRAW and REGEN, see Refreshing the Screen Display on page 64. Setting the SORTENTS System Variable The initial value for the SORTENTS system variable is 96, which means sorting is turned on only for plotting and PostScript output. By default, when you use the DRAWORDER command, object sorting is turned on for all sorting operations, and SORTENTS is automatically set to 7, which is the sum of all the bit-code values. For operations such as object selection and display redraws, objects are displayed in the most efficient manner possible without adhering to a specific drawing order. Changing SORTENTS may temporarily disable the display order of the objects you have just ordered. However, if you use DRAWORDER again, the drawing order is restored. In large drawings, regeneration and redrawing can be slower when SORTENTS is on. Setting SORTENTS to 0 turns off the sort order, which means AutoCAD displays objects in the most efficient manner possible without adhering to a specific drawing order. For more information about SORTENTS and its code values, see the Command Reference. 44 Chapter 6 Creating Objects

23 Creating Solid-Filled Areas You can create triangular and quadrilateral areas filled with a color. For quicker results, create these areas with the FILLMODE system variable off, and then turn on FILLMODE to fill the finished area. You don t see the area outline until it is complete. solid-filled areas Solid-filled areas used to depict buildings To create a triangular solid-filled area 3 From the Draw menu, choose Surfaces D Solid. Specify the first point (). 3 Specify the second point (). 4 Specify the third point (3). Then press ENTER. 5 Press ENTER again to exit the command. When you create a quadrilateral solid-filled area, the sequence of the third and fourth points determines its shape. Compare the following illustrations: Command line SOLID Related 3DFACE creates a 3D face. Creating Solid-Filled Areas 45

24 Creating Regions Regions are D enclosed areas you create from closed shapes called loops. A loop is a curve or a sequence of connected curves that defines an area on a plane with a boundary that does not intersect itself. Loops can be combinations of lines, polylines, circles, arcs, ellipses, elliptical arcs, splines, 3D faces, traces, and solids. The objects that make up the loops must either be closed or form closed areas by sharing endpoints with other objects. The objects must also be coplanar (on the same plane). You can create regions out of multiple loops and out of open curves whose endpoints are connected and form loops. If the open curves intersect in their interior, they cannot form a region. Objects such as 3D polylines and face meshes can be converted to regions by being exploded. You cannot form regions from open objects that intersect to form a closed area: for example, intersecting arcs or self-intersecting curves. You can apply hatching and shading to regions, and you can analyze properties such as their area and moments of inertia. To create regions by selecting objects From the Draw menu, choose Region. Select objects to create the region (must be closed loops). 3 Press ENTER. basic shapes that can form regions A message on the command line indicates how many loops were detected and how many regions were created. Command line REGION Related BOUNDARY creates regions by first creating polyline boundaries from intersecting objects, whether they share endpoints or not. BHATCH creates an associative hatch boundary. BLOCK creates a compound object (a block definition) from a group of objects. To create regions by using boundaries From the Draw menu, choose Boundary. In the Boundary Creation dialog box under Object Type, select Region. 3 If you want to limit the number of objects that AutoCAD analyzes when you use Pick Points to create boundaries (by default, AutoCAD analyzes all objects visible in the current viewport), under Boundary Set, choose the New button. 46 Chapter 6 Creating Objects

25 4 Select the objects that you want AutoCAD to analyze when you define boundaries and press ENTER. 5 Choose Pick Points. 6 Specify a point in your drawing inside each area that you want to be defined as a region and press ENTER. region internal point Command line BOUNDARY Related REGION creates a region object from a selection set of existing objects. BHATCH fills an enclosed area or selected objects with a hatch pattern. You can create composite regions by subtracting, combining, or finding the intersection of regions. You can then extrude or revolve composite regions to create complex solids (see chapter 7, Working in Three-Dimensional Space ). When you subtract one region from another, you first select the region from which you want to subtract. For example, to calculate how much carpeting is needed for a floor plan, select the outer boundary of the floor space and subtract all the uncarpeted areas, such as pillars and counters. Find the area of the resulting region with the AREA command. To create a composite region by subtraction From the Modify menu, choose Solids Editing Subtract. Select the region from which to subtract () and press ENTER. 3 Select the region to subtract (). selected regions result a composite region Command line SUBTRACT Related UNION and INTERSECT also create composite regions. You can select regions in any order to unite them with the UNION command or to find their intersection with the INTERSECT command. AutoCAD ignores objects within the selection set that are not regions. Creating Regions 47

26 The following illustration shows the uniting of two regions. selected regions result The following illustration shows the intersection of three regions, which you find using the INTERSECT command. selected intersecting regions result You can select in any order the regions whose intersection you want to find. The resulting object is also a region. Hatching Areas islands overhanging edges Hatching fills a specified area in a drawing with a pattern. You can hatch an enclosed area or a specified boundary using the BHATCH and HATCH commands. BHATCH creates associative or nonassociative hatches. Associative hatches are linked to their boundaries and are updated when the boundaries are modified. Nonassociative hatches are independent of their boundaries. BHATCH defines boundaries automatically when you specify a point within the area to be hatched. Any whole or partial objects that are not part of the boundary are ignored and do not affect the hatch. The boundary can have overhanging edges and islands (enclosed areas within the hatch area) that you choose to hatch or leave unhatched. You can also define a boundary by selecting objects. 48 Chapter 6 Creating Objects

27 HATCH creates nonassociative hatches only. It is useful for hatching areas that do not have closed boundaries. See Creating a Hatch Using Point Acquisition on page 50. HATCH is available only on the command line. After you ve created a hatch, you can edit it with HATCHEDIT or explode it into composite lines using the EXPLODE command. Creating an Associative Hatch Hatched areas created with BHATCH are associative by default. You can remove hatch associativity at any time or you can change the default to create a nonassociative hatch. If you specify points to create an associative hatch, specify only one internal point per hatch block placement. Specifying more than one internal point can produce unexpected results when you edit the hatch boundary. hatched object To hatch an enclosed area result of editing boundary with nonassociative hatch result of editing boundary with associative hatch From the Draw menu, choose Hatch. In the Boundary Hatch dialog box, choose Pick Points. 3 Specify a point in your drawing inside each area you want to hatch. If you make a mistake, you can right-click and choose Clear All or Undo Last Select/Pick from the shortcut menu. 4 To preview the hatch, right-click and choose Preview. 5 Press ENTER to return to the Boundary Hatch dialog box. 6 Choose OK to apply the hatch. By default, AutoCAD uses the Flood island detection method to define boundaries from the specified points, and the Normal island detection style to apply the hatch. See Defining Hatch Boundaries on page 5 and Using Island Detection Styles on page 54. Hatching Areas 49

28 To hatch selected objects From the Draw menu, choose Hatch. In the Boundary Hatch dialog box, choose Select Objects. 3 Select the object or objects you want to hatch. The objects need not form a closed boundary. You can also specify any islands by selecting objects within other selected objects. If you make a mistake, you can right-click and choose Clear All or Undo Last Select/Pick from the shortcut menu. 4 To preview the hatch, right-click and choose Preview. 5 Press ENTER to return to the Boundary Hatch dialog box. 6 Choose OK to apply the hatch. By default, AutoCAD uses the Normal island detection style to apply the hatch. See Using Island Detection Styles on page 54. Command line BHATCH Related HATCH creates a nonassociative hatch. BOUNDARY creates a polyline or region boundary. NOTE Due to the large number of combinations of objects that can be hatched, editing hatched geometry can produce unexpected results. If an error occurs, delete the hatch object and rehatch. Creating a Hatch Using Point Acquisition You can define a hatch boundary by specifying points directly. For example, you may want to illustrate a pattern fill in a small section of a drawing, as shown in the following illustration points specified to define hatch boundary result 50 Chapter 6 Creating Objects

29 To define a boundary by point acquisition On the command line, enter hatch. Enter the name of the hatch pattern. 3 Specify the hatch pattern scale and angle. 4 At the Select Objects prompt, press ENTER, because you are specifying points and not selecting objects. 5 Using points to create a hatch boundary creates a polyline boundary. Enter y to retain the polyline boundary, or n to discard it after the hatching is completed. 6 Specify the points that define the boundary. 7 Enter c (Close) and press ENTER. Defining Hatch Boundaries Boundaries can be any combination of lines, arcs, circles, D polylines, ellipses, splines, blocks, and paper space viewports (see Creating Floating Viewports on page 530). Each boundary component must be at least partially within the current view. When you use Pick Points to define boundaries, the way in which AutoCAD derives the boundary definition from the specified point depends on the specified boundary set and the island detection method. Using Island Detection Methods Island detection methods specify whether to include objects within the outermost boundary as boundary objects when you are using Pick Points. These internal objects are known as islands. By default, AutoCAD uses the Flood island detection method. The Flood method includes islands as boundary objects, as shown in the following illustration. How AutoCAD hatches the detected islands depends on the island detection style (see Using Island Detection Styles on page 54). The following illustration uses the Normal island detection style, meaning that islands remain unhatched and islands within islands are hatched. Hatching Areas 5

30 internal point internal point selected boundaries detected result If you do not want to include islands as boundary objects when using Pick Points, use the Ray Casting island detection method. Ray Casting runs a line from the point you specify to the nearest object and then traces the boundary in a counterclockwise direction, thus excluding islands from boundary detection. You can find these options on the Advanced tab of the Boundary Hatch dialog box. When you define boundaries by selecting objects rather than specifying points, the island detection method has no effect on how AutoCAD derives the boundary definition. Removing Islands When you use Pick Points to define your boundaries, you can remove any detected islands from your boundary definition. In the following procedure, you remove islands so that the part is hatched as illustrated. internal point boundaries detected islands to remove (solid boundaries) result 5 Chapter 6 Creating Objects

31 To remove islands from the hatch area From the Draw menu, choose Hatch. In the Boundary Hatch dialog box, choose Pick Points. 3 Specify a point in your drawing inside the hatch area. 4 Press ENTER. 5 Choose Remove Islands. 6 Select the islands for removal (see the solid boundaries in the middle illustration) and press ENTER. 7 Choose OK to apply the hatch. Command line BHATCH Using Boundary Sets When you use Pick Points to define your boundaries, AutoCAD analyzes all objects in the boundary set to derive the boundary definition. The boundary set is the set of objects that AutoCAD treats as eligible for analysis when defining boundaries from a specified point. By default, the boundary set consists of all objects fully or partially visible in the current viewport. So, if 00 objects are currently visible, AutoCAD analyzes all 00 objects when you specify a point, regardless of the location of that point. Analysis of all of these objects can be time-consuming in a complex drawing. To hatch a small area of a complex drawing, you can define a custom boundary set. When you specify a point within the boundary set, AutoCAD does not analyze objects not included in the boundary set. Boundary sets are also useful for applying different hatch styles in different sections of a drawing. In the following example, you create a boundary set within a map before defining and hatching your boundary. To define a boundary set in a complex drawing From the Draw menu, choose Hatch. In the Boundary Hatch dialog box, choose the Advanced tab. 3 In the Boundary Set section of the Advanced tab, choose Select New Boundary Set. Hatching Areas 53

32 4 At the Select Objects prompt, select the objects you want to include in the boundary set () and press ENTER. 3 new boundary set internal point result 5 In the Boundary Hatch dialog box, choose Pick Points. 6 Specify the internal point () to define the boundary, and press ENTER. 7 Choose OK to apply the hatch. Using Island Detection Styles You can control how AutoCAD hatches islands detected as boundaries using the three island detection styles: Normal, Outer, and Ignore. You can find these styles on the Advanced tab of the Boundary Hatch dialog box. The styles are also available from a shortcut menu by right-clicking in the drawing area while selecting objects or specifying points from which to define your boundaries. NOTE Do not confuse island detection styles (Normal, Outer, and Ignore), which control the treatment of boundary definitions, with island detection methods (Flood and Ray Casting), which control the creation of boundary definitions from a specified point. The Normal style hatches inward from the outer boundary. If it encounters an internal intersection, it turns off hatching until it encounters another intersection. Thus, areas separated from the outside of the hatched area by an odd number of intersections are hatched, and areas separated by an even number are not. The Outer style hatches inward from the outer boundary and stops at the next boundary. The Ignore style hatches the entire enclosed area, ignoring internal boundaries. 54 Chapter 6 Creating Objects

33 Normal Outer Ignore Hatch styles If a hatch line encounters a text, attribute, shape, trace, or solid-fill object, and if the object is selected as part of the defined boundary, AutoCAD does not hatch through the object. You can draw a pie slice, for example, label it with text, and hatch it, and the text remains readable. If you want to hatch through such objects, use the Ignore style. default hatching of text You cannot hatch the interiors of traces and solids because AutoCAD does not accept their outlines as boundaries. Using Hatch Patterns AutoCAD supplies a solid fill and more than 50 industry-standard hatch patterns that you can use to differentiate the components of objects or represent object materials. AutoCAD supplies 4 hatch patterns that conform to the ISO (International Standardization Organization) standards. When you select an ISO pattern, you can specify a pen width, which determines the lineweight in the pattern. industry-standard hatch patterns You can use a pattern supplied with AutoCAD or one from an external pattern library. For a table of the hatch patterns supplied with AutoCAD, see appendix E, Standard Libraries, in the Command Reference. You can also define your own hatch pattern using the current linetype with the User Defined Pattern option, or you can create more complex hatch patterns. For information about creating hatch patterns, see chapter, Linetypes and Hatch Patterns, in the Customization Guide. To reduce file size, a hatch pattern is defined in the drawing database as a single graphical object. Hatching Areas 55

34 In the first procedure that follows, you use the Hatch Pattern Palette dialog box to choose an ISO pattern. In the second procedure, you create a simple line pattern by defining the spacing between the lines and creating a second set of lines at 90 degrees to the original lines. To use an ISO hatch pattern From the Draw menu, choose Hatch. In the Boundary Hatch dialog box, choose the Quick tab. 3 Under Type, choose Predefined. 4 Under Pattern, choose an ISO pattern name from the list, or if you prefer to choose the pattern by viewing preview images, choose the [...] button next to the Pattern list. 5 In the Hatch Pattern Palette dialog box, choose the ISO tab. 6 Choose a pattern and choose OK. 7 In the Boundary Hatch dialog box, choose Pick Points. 8 Specify an internal point and press ENTER. 9 To preview the hatch, right-click and choose Preview. If the pattern is not displayed the way you want, you may need to adjust the pattern, scale, or angle. Use the Preview button in the Boundary Hatch dialog box to preview the hatch with the new settings. 0 Press ENTER to return to the Boundary Hatch dialog box. Choose OK to apply the hatch. To define a hatch pattern From the Draw menu, choose Hatch. In the Boundary Hatch dialog box, choose the Quick tab. 3 Under Type, choose User Defined. 4 Under Spacing, enter the spacing between lines. 5 Select Double to add lines at 90 degrees to the original. 6 Choose Pick Points. 7 Specify an internal point and press ENTER. 8 Choose OK to apply the hatch. Command line BHATCH 56 Chapter 6 Creating Objects

35 Custom and Proxy Objects Many software vendors other than Autodesk use the AutoCAD Runtime Extension programming language to write programs that create graphical and nongraphical objects you can insert into AutoCAD drawings. Objects created by ObjectARX applications are called custom objects. To display and use custom objects in AutoCAD drawings, the ObjectARX application that created them must be available to AutoCAD. If not, AutoCAD temporarily replaces the custom object with a proxy object. Later, when the application is available to AutoCAD, the proxy object is replaced by the custom object. You encounter proxy objects when You open a drawing containing custom objects, but the application that created them is not installed on your system You unload the ObjectARX application that created the custom object in the current drawing AutoCAD displays the Proxy Information dialog box when proxy objects are displayed. The dialog box tells you the total number of proxy objects in the drawing (both graphical and nongraphical) and the name of the missing application and provides additional information about the proxy object type and display state. You can use the dialog box to control the display of proxy objects. Working with Named Objects AutoCAD drawing files contain both graphical and nongraphical objects. You use graphical objects, such as lines, arcs, and circles, to create your designs. At the same time, you use nongraphical information, called named objects, to manage the design. Named objects include such items as text styles, dimension styles, named layers, and named views. Named objects help you design more efficiently. For example, if you use a set of linetype properties frequently, you can save the properties as a named linetype and then apply the linetype to lines in your drawing at any later time. You can define and save different ways to view a drawing. For example, you can save multiple UCSs (user coordinate system), so you can easily switch from one UCS to another during a drawing session. You can also save multiple views and viewport configurations. Custom and Proxy Objects 57