Offsetting an Object a Specified Distance

Specifying a distance is the default method and the most commonly used. When specifying a distance, you can simply type in the distance or pick two points. If you pick two points, AutoCAD will measure the distance between the two points and use that as the offset distance.

Offsetting Through a Point

It is also possible to offset objects through a point that you pick in the drawing using the Through option. Typically, this is done in conjunction with object snaps so that you can snap to specific key features in your drawing. The easiest way to specify the Through option is to press <Enter> when AutoCAD prompts you to Select object to offset or .

Offset Options

By default, the OFFSET command will copy the selected object on the same layer as the original, or source, object. The Layer option allows you to offset an object on the current layer. The Erase option allows you to erase the original object. The current settings are displayed at the command line each time you select the OFFSET command.

Arraying Objects

An array consists of multiple objects copied in a regular pattern. There are three types of arrays in AutoCAD (see Figure 8-3):

• Rectangular Pattern of evenly distributed objects arranged in rows and columns

• Path Linear pattern of evenly distributed objects that follow a predefined path

• Polar Circular pattern of evenly distributed objects arranged around a center point

The AutoCAD array tools are located on the Array flyout menu on the Modify panel on the Home tab of the ribbon as shown in Figure 8-4.

By default, arrayed objects are associated like AutoCAD blocks and dimensions so that they act as one complex unit and individual objects maintain a set relationship to each other. If one object in an array is selected, all of the objects in the array are highlighted. The Array context tab of the ribbon shown in Figure 8-5 is swapped in place of the current tab of the ribbon at the top of the AutoCAD drawing window, so it is easy to edit the array without starting over.

The Array context tab of the ribbon allows you to change any of the array properties, update or replace individual array objects, and even reset an array back to its original settings while maintaining the array’s associativity. The Edit Source tool allows you to update a single array object individually using regular AutoCAD commands and then elect to either save or discard changes via an Edit Array panel that gets appended to the right end of the current tab of the ribbon.

In addition to the Array context tab of the ribbon, many array options and settings are provided via right-click shortcut menus and multifunctional grips that are displayed when an array is selected in the drawing, as shown in Figure 8-6.

Creating a Rectangular Array

The Rectangular Array tool allows you to copy objects equidistantly to create any combination of rows and columns (see Figure 8-7).

After you choose the Rectangular Array tool, select the object(s) you want to array, and press <Enter>. AutoCAD automatically creates a default array with 3 rows and 4 columns. AutoCAD also replaces the standard ribbon with the Array Creation context tab of the ribbon and turns on multifunctional grips. To specify different array options other than the defaults, you can either use the Array Creation context tab of the ribbon, pick a grip to edit in grip mode, or select one of the following command options:

• Associative Specify whether to create an array of associated objects, or individual objects

• Base Point Specify a new base point

• COUnt Specify the number of rows and columns

• Spacing Change spacing between rows and columns

• COLumns Change the number and spacing of columns

• Rows Change the number and spacing of rows

• Levels 3D setting that allows you to change the number of levels in the Z-axis

• eXit Accept all settings and end the command

Exercise 8-2 Creating a Rectangular Array

Start a new drawing using the acad.dwt drawing template.

Draw the geometry shown in Figure 8-8.

Select the Rectangular Array tool from the Modify panel on the Home tab of the ribbon.

Select the circle, and press <Enter>.

Select the COUnt option.

Specify 3 columns and 3 rows.

Select the Spacing option.

Type 5.25<Enter> to specify the distance between columns.

Type 3.25<Enter> to specify the distance between rows.

Press <Enter> again to exit the Rectangular Array tool.

Hold down the <Ctrl> key, and select the circle at the center of the part.

Select the Erase tool, or press the <Del> key and erase the circle.

Save your drawing as CH08_EXERCISE2. Your drawing should look like Figure 8-9.

Creating a Path Array

The Path Array tool allows you to copy objects evenly along a path that can be defined using a line, polyline, spline, arc, circle, or ellipse. You have the option of either specifying the distance between each object or letting AutoCAD figure it out based on the total distance and number of copies, as shown in Figure 8-10.

By default, path array objects are associative so that they will automatically update if the associated path curve changes. For instance, if you choose to divide the path into equal segments, the spacing between the objects automatically adjusts if the length of the path changes.

After you choose the Path Array tool and select the object(s) you want to array, you define the path you want the selected object(s) to follow by selecting one of the valid object types listed above. Once the path is defined and you press <Enter>, AutoCAD automatically creates a default array. AutoCAD also replaces the standard ribbon with the Array Creation context tab of the ribbon and turns on multifunctional grips. To specify different array options other than the defaults, you can either use the Array Creation context tab of the ribbon, pick a grip to edit in grip mode, or select one of the following command options:

• Associative Specify whether to create an array of associated objects or individual objects

• Method Specify whether to divide the path into equal segments or measure the distance between arrayed objects

• Base Point Specify a new base point

• Tangent direction Specify how the arrayed items are aligned relative to the starting direction

• Items Change the total number of items

• Rows Change the number and spacing of rows

• Levels 3D setting that allows you to change the number of levels in the Z-axis

• Align Items Specify whether to align each item with the path direction

• Z Direction 3D setting that controls whether items follow their original Z direction

• eXit Accept all settings and end the command

Exercise 8-3 Creating a Path Array

Start a new drawing using the acad.dwt drawing template.

Draw the circle and ellipse shown in Figure 8-11.

Select the Path Array tool from the Modify panel on the Home tab of the ribbon.

Select the circle and press <Enter>.

Select the ellipse when prompted to select a path curve.

Select the Method option.

Select the Divide option.

Select the Items option.

Type 8<Enter> to specify the number of items (copies).

Press <Enter> again to exit the Path Array command. Your drawing should look like Figure 8-12.

Select the ellipse so grips are displayed.

Select one of the perimeter grips on the ellipse, and resize it by stretching the point in or out. Notice how the array objects are automatically updated based on the size of the ellipse.

Save your drawing as CH08_EXERCISE3.

Creating a Polar Array

The Polar Array tool allows you to create a circular pattern of objects arranged around a center point by specifying either the number of copies to make and the angle to fill (0°–360°) or the included angle between each object as shown in Figure 8-13.

First you choose the Polar Array tool and select the object(s) you want to array. Then you define the center point about which to rotate the objects while they are copied by either picking a point in your drawing or inputting a coordinate value via the keyboard.

If you enter the total number of copies, AutoCAD will calculate the included angle between objects based on the current angle to fill. If you select the Angle between option, AutoCAD will calculate the angle to fill based on the included angle and the total number of items specified.

Once the center point is defined and you press <Enter>, AutoCAD automatically creates a default array. AutoCAD also replaces the standard ribbon with the Array Creation context tab of the ribbon and turns on multifunctional grips. To specify different array options other than the defaults, you can either use the Array Creation context tab of the ribbon, pick a grip to edit in grip mode, or select one of the following command options:

• Associative Specify whether to create an array of associated objects or individual objects

• Base Point Specify a new base point

• Items Change the total number of items

• Angle Between Change the angle between items

• Fill Angle Change the angle between the first and the last item in the array

• ROWs Change the number and spacing of rows

• Levels 3D setting that allows you to change the number of levels in the Z-axis

• ROTate items Specify whether items are rotated while they are arrayed

• eXit Accept all settings and end the command

Exercise 8-4 Creating a Polar Array

Start a new drawing using the acad.dwt drawing template.

Draw the geometry shown in Figure 8-14.

Select the Polar Array tool from the Modify panel on the Home tab of the ribbon.

Select the two angled lines, and press <Enter>.

Select the bottom endpoint of the middle vertical line when prompted to specify a center point.

Select the Items option.

Type 8<Enter> to specify the number of items (copies).

Press <Enter> again to exit the Polar Array tool.

Select the array you just created. The Array context tab of the ribbon is displayed at the top of the drawing window.

Change the Items value from 8 to 16 on the top of the Items panel on the left side of the Array context tab of the ribbon. The total number of array objects will update.

Press the <Esc> key to deselect the array so it is no longer highlighted.

Save your drawing as CH08_EXERCISE4. Your drawing should look like Figure 8-15.

Trimming Objects

Objects are trimmed using the TRIM command. When you start the TRIM command, AutoCAD prompts you to select your cutting edges. These cutting edges determine the stopping boundaries of the trimmed objects. Select the cutting edges using AutoCAD’s standard selection methods. Once you’ve selected the cutting edges, press <Enter>, and AutoCAD will prompt you to select the object to trim. As you pick each object, AutoCAD will trim the object back to the cutting edge. The portion of the object you select is the part that is deleted. In order for an object to be trimmed, it must cross one of the cutting edges. If AutoCAD cannot detect an intersection between the cutting edges and the object to be trimmed, it displays a message: Object does not intersect an edge.

Selecting Cutting Edges. In some cases, the cutting edges and the objects to be trimmed may be the same objects. AutoCAD does not distinguish between the cutting edges and the objects to be trimmed. You can select a cutting edge as an object to be trimmed.

Trim Options. After you select the cutting edges, the TRIM command has a number of options. They are listed in the following table.

Some closed objects, such as circles or ellipses, require that the object intersect a cutting edge in at least two places. This is because these objects have no endpoints and must therefore be trimmed between two edges. If you attempt to trim one of these objects with only one cutting edge, AutoCAD will display the message: Object must intersect twice. Some objects cannot be trimmed, such as text and blocks.

Exercise 8-5 Trimming Objects

Start a new drawing using the acad.dwt drawing template.

Draw a circle with a radius of 5.

Draw three lines that are 6 units long, starting at the center of the circle at an angle of 80°, 90°, and 100°, respectively, as shown in Figure 8-18.

Use the OFFSET command, and offset each line .5 unit, as shown in Figure 8-19.

Start the TRIM command. AutoCAD prompts you to Select objects or <select all>:.

Press <Enter> to select all the objects as cutting edges. AutoCAD prompts you: Select object to trim or shift-select to extend or .

Pick the points shown in Figure 8-19 to trim the objects so that all overlapping lines at the corners are cleaned up. AutoCAD continues to prompt you: Select object to trim or shift-select to extend or .

Select the eRase option. AutoCAD prompts you to Select objects to erase:. Select the three vertical lines, the 80° line, and the 100° line that start at the circle center point as shown in Figure 8-19. Press <Enter> to erase the selected objects. Your drawing should look like Figure 8-20.

AutoCAD again prompts you to Select object to trim or shift-select to extend or . Press <Enter> or <Esc> to exit the TRIM command.

Draw two circles with a diameter of 0.3125 by snapping to the endpoints of the angled lines as shown in Figure 8-21.

Start the OFFSET command, and offset each of these circles 0.6875 toward the outside of each circle, as shown in Figure 8-21.

Zoom in on the two circles at the top of the drawing. Start the TRIM command, and press <Enter> to select all the objects as cutting edges, and then select the six trim points shown in Figure 8-21.

Choose the eRase option, and select the objects shown in Figure 8-22 to erase. Press <Enter> to erase the objects. Press <Enter> again to end the TRIM command.

Save your drawing as CH08_EXERCISE5.

Extending Objects

Extending objects is similar to trimming them; the objects simply get longer instead of shorter. The EXTEND command has options similar to the TRIM command except you are prompted to select boundary edges instead of cutting edges. Whether they are called boundary or cutting edges, the concept is the same; the edge determines where the object is extended.

Extend Options. The options for the EXTEND command are identical to those for the TRIM command with the exception of the eRase option. Because extending is an additive process (you are adding length to objects) and the eRase option is a subtractive process, this option is omitted from the EXTEND command.

Using the <Shift> Key to Switch Between Trim and Extend. Because the EXTEND and TRIM commands are so similar, AutoCAD provides an easy way to switch back and forth between them. You may have noticed that in the TRIM command, after you select the cutting edges, AutoCAD prompts you to Select object to trim or shift-select to extend or . By holding down the <Shift> key while selecting the objects to extend, you can use the TRIM command to trim objects. The same is true for the EXTEND command. After you select the boundary edges, AutoCAD prompts you to Select object to extend or shift-select to trim or . While the <Shift> key is depressed, the EXTEND command will trim objects, using the boundary edges as the cutting edges.

Exercise 8-6 Extending Objects

Continue from Exercise 8-5.

Start the OFFSET command and offset the large circle 3.5 units toward the center of the circle. Repeat the OFFSET command, and offset the new circle .5 unit toward the center.

Draw two lines, each 8 units long, from the center of the circle at an angle of 85° and 95°, respectively.

Draw two more short lines, each 3 units long, from the center of the circle at an angle of 60° and 120°, respectively.

Start the OFFSET command, set the eRase option to Yes so the original lines are erased, and set the offset distance to .25. Offset the two short lines. Offset the left-hand line to the right, and the right-hand line to the left. Your drawing should look like Figure 8-23.

Zoom in on the top of the drawing, and start the EXTEND command. AutoCAD prompts you to Select objects or <select all>:. Select the two 8″–long angled lines, and press <Enter> to make them the boundary edges.

AutoCAD prompts you to Select object to extend or shift-select to trim or . Pick the two small arc segments nearest to the angled lines selected in step 6 as shown in Figure 8-24 so that the arcs extend out to meet the boundary edges.

Select the ERASE command, and delete the two 8″–long angled lines used as boundary edges in step 7.

Zoom out to see the entire drawing, and select the EXTEND command again. Select the two outer circles and the two angled lines as boundary edges as shown in Figure 8-25, and press <Enter>.

Pick near the ends of the two angled lines using the pick points shown in Figure 8-25 to extend the lines to meet the outer circle.

Hold down the <Shift> key to enter Trim mode. Select the inner circle using the pick point shown in Figure 8-25, and trim it into the small arc segment shown in Figure 8-26.

Hold down the <Shift> key to enter Trim mode. Select the two angled lines using the pick points shown in Figure 8-25, and trim them to meet the small arc segment created in step 11 as shown in Figure 8-26.

Press <Enter> to end the EXTEND command.

Start the TRIM command, and select the two angled lines that were extended in step 10 as cutting edges and press <Enter>.

Pick the outer circle near the bottom as shown in Figure 8-25 to trim it into the large arc segment shown at the top in Figure 8-26.

Press <Enter> to end the TRIM command.

Save your drawing. Your drawing should look like Figure 8-26.

Creating Fillets

To create a fillet, you specify a fillet radius and select two objects. AutoCAD will place an arc between the two objects and trim and extend the objects as needed. The points where you select the objects determine where the arc is placed. AutoCAD will place the fillet so that the selected portions will remain (see Figure 8-28).

After selecting the first object, AutoCAD provides a preview of the fillet when you pass your cursor over the second object. You can use the Radius option to change the radius value anytime before you select the second object.

Radius Option. When you start the FILLET command, the current radius setting is listed at the command line. The Radius option allows you to set the fillet radius. The fillet radius is stored in the FILLETRAD system variable, and once set AutoCAD will retain the setting until you change it. Setting the Radius option to 0 will result in AutoCAD squaring off a corner.

You can create a fillet between open objects (lines, arcs, and elliptical arcs) as well as closed objects (circles and ellipses). When you select a closed object, AutoCAD doesn’t actually trim the closed object but simply draws a tangent fillet arc (see Figure 8-29).

Multiple Mode. The Multiple option puts you into Multiple mode and allows you to create multiple fillets in a single command. In Multiple mode, the FILLET command simply repeats until you press <Enter> or <Esc>. The Undo option allows you to undo the last fillet while in Multiple mode.

Trim Mode. The Trim option allows you to turn Trim mode on and off. With Trim mode turned on, objects are trimmed or extended to the fillet arc. With Trim mode turned off, AutoCAD creates the fillet arc but leaves the source objects unchanged. Like the Radius option, the Trim setting is retained after the FILLET command is complete until you change it.

The Polyline Option. The Polyline option allows you to add a fillet radius to all the intersections in a polyline object.

Capping Two Parallel Lines Using the Fillet Tool

If you fillet two parallel lines, AutoCAD will create a rounded end cap between the two lines. In this case, AutoCAD will ignore the Radius setting and create a 180° arc using half the distance between the lines as the radius. If the lines are different lengths, the first object you select will determine the start point of the arc. The other line will be trimmed or extended to match the first selected object (see Figure 8-30).

Exercise 8-7 Creating a Fillet

Continue from Exercise 8-6.

Start the FILLET command. AutoCAD prompts you to Select first object or .

Choose the Multiple option to turn on Multiple mode.

Choose the Radius option and type .5<Enter> to set the fillet radius.

Pick the lines and arc shown in Figure 8-31 to round the outer corners. AutoCAD will round the corners and continue prompting you to select objects.

Choose the Radius option and type .25<Enter> to set the fillet radius.

Pick the lines and arc shown in Figure 8-31 to round the inner corners. When you’ve finished rounding the four corners, press <Esc> to end the FILLET command.

Start the ARRAY command, and create a polar array of the pointed geometry at the top of the drawing. Center the array about the center of the circle, and create 36 items through 360°, rotating the objects as they are copied.

Repeat the ARRAY command, and create a polar array of the rounded wedge. Center the array about the center of the circle, and create six items through 360°, rotating the objects as they are copied. Your drawing should look like Figure 8-32.

Save your drawing.

Creating Chamfers

The CHAMFER command is used to create angled corners between two intersecting objects. Drawing a chamfer between intersecting objects is similar to drawing a fillet. However, instead of a fillet radius, you need to provide two distances from the intersection along each object, or a distance and an angle for the chamfer (see Figure 8-33).

The CHAMFER command has two methods for creating chamfers: distance and angle. The mEthod option allows you to select which chamfer method to use.

After selecting the first object, AutoCAD provides a preview of the chamfer when you pass your cursor over the second object. You can use the Distance or Angle option to change the chamfer size or angle any time before you select the second object.

Distance Method. With the Distance method, you specify the distance from the intersection along each line. From the intersection, AutoCAD subtracts the first chamfer distance from the first object and the second chamfer distance from the second object and then draws a line between these two points. The Distance option allows you to set the chamfer distances. The first distance is applied to the first object you select, and the second distance is applied to the second object.

If the chamfer distances are equal, a 45° chamfer is drawn. When you set the first distance, AutoCAD sets the default value of the second distance to the first distance. To accept this default, just press <Enter> when prompted for the second chamfer distance.

Angle Method. The Angle method uses a distance and angle to determine the chamfer line. The distance is subtracted from the first object selected to determine the starting point, and the chamfer line is drawn at the specified angle until it intersects with the second object. By default, the angle is measured in a counterclockwise direction from the first object (see Figure 8-34).

The Polyline Option. The Undo, Polyline, Trim, and Multiple options work the same way as on the FILLET command. When chamfering a polyline with the Polyline option, the first and second objects are determined by the order in which the polyline was drawn. When in doubt, or if you are not getting the results you’re expecting, your best bet may be not to use the Polyline option and just chamfer the polyline segments individually.

Exercise 8-8 Creating a Chamfer

Continue from Exercise 8-2. If you’ve closed the drawing, open drawing CH08_EXERCISE2.

Start the CHAMFER command, and select the Angle option. AutoCAD prompts you to Specify chamfer length on the first line:. Type .75<Enter> to set the length.

AutoCAD prompts you to Specify chamfer angle from the first line:. Type 60<Enter> to set the chamfer angle.

AutoCAD prompts you to Select first line or . Pick the objects shown in Figure 8-35. AutoCAD chamfers the corner. Note that the .75 distance is taken off of the first line you selected.

Because this chamfer comes very close to the hole, type U<Enter> to undo the last chamfer.

Restart the CHAMFER command, and select the Distance option. Set the first distance to .5. AutoCAD sets the default value of the second distance to match the first. Press <Enter> to accept the default. AutoCAD prompts you to Select first line or .

Select the Multiple option and chamfer the four corners of the part. Your drawing should look like Figure 8-36.

Save your drawing.

Creating a Gap in an Object

When you start the BREAK command, AutoCAD prompts you to select an object. By default, when you select the object, the point you pick on the object becomes the first break point, and AutoCAD will prompt you to select the second break point. If the point you select is not the point you want, you can use the First option to repick the first break point on the selected object.

Once you specify the first break point, AutoCAD prompts you for the second break point and breaks the object between the two points.

Breaking an Object Exactly at a Point

There may be times when you want to break the object in two without creating a physical gap. To break an object without creating an opening, simply use the @ symbol to specify the second point. When you use the @ symbol, AutoCAD will place the second point at the same coordinate as the first point. The end result is the object is broken in two without creating a gap.

Breaking Circles, Xlines, and Rays

Depending on the type of object you select, the BREAK command will create new objects. When you break a line, AutoCAD simply creates two lines. However, when you break a circle, Xline, or ray, AutoCAD will create different types of objects.

Circle. When you break a circle, AutoCAD converts the circle to an arc. The order in which you select the points will determine which portion of the circle is kept. AutoCAD will remove the portion of the circle starting at the first in a counterclockwise direction. Figure 8-37 shows the results of selecting different points along a circle.

Xlines and Rays. When you break an Xline, AutoCAD will create two rays with the starting points of the rays located at the first and second break points. Breaking a ray will result in a line and a ray.

Selecting the Second Points

When you select the second break point, there are a couple of things to keep in mind. First, if you select the second point somewhere away from the object, AutoCAD will project a break point along a line perpendicular to the object passing through the selected point. Second, if the second break point lies past the end of the object, AutoCAD will simply remove everything between the first point and the end of the object. Figure 8-38 shows examples of these.

Exercise 8-9 Breaking Objects

Continue from Exercise 8-1. If you’ve closed the drawing, open drawing CH08_EXERCISE1.

Start the BREAK command, and select the circle near the bottom quadrant, between the two vertical lines. AutoCAD prompts you to Specify second break point or . Pick anywhere near the circle to break the circle into an arc segment. Don’t worry about the final length of the arc segment.

Restart the BREAK command. AutoCAD prompts you to Select object:. Hold down the <Shift> key, and right-click to bring up the Object Snap menu. Choose Midpoint and select the centerline. This selects the line and places the first break point at the midpoint of the line. AutoCAD prompts you to Specify second break point or .

Type @<Enter> to break the line at the midpoint. Drag your cursor over a portion of the centerline. AutoCAD will highlight half of the centerline.

Start the FILLET command, and set the radius to 25. Turn on Multiple mode, and add fillets between the arc and line segments. Your drawing should look like Figure 8-39.

Save your drawing.

The LENGTHEN Command Options

When lengthening an object, AutoCAD must know how much length to add to or subtract from the object. Once it knows what changes to make, the LENGTHEN command will prompt you to select an object to lengthen. You can either select a single object or use the Fence selection method to drag a fence crossing line across the items you wish to lengthen. AutoCAD will keep prompting you to select objects, allowing you to lengthen multiple objects within a single command.

The LENGTHEN command options provide four different methods for altering the length of an object.

DElta Option. The DElta option allows you to specify a discrete length to add to or subtract from the object. When you choose the DElta option, AutoCAD asks you to enter a delta length and then prompts you to select an object. The length you specify is then added to the object at the end closest to where you select. A positive delta value will increase the length, and a negative delta will shorten the object.

The DElta option also includes an Angle option. This allows you to modify the included angle of an arc. By default, positive angles add length in the counterclockwise direction, and negative angles subtract length in the clockwise direction.

Percent Option. The Percent option allows you to scale the line by a percentage value. A percent value of 200 will make an object twice as long. A value of 50 will make it half as long. A value of 110 will add 10% to the length of the object. A value of 100 will leave the object unchanged.

Total Option. The Total option allows you to set the total length of an object. If the value is greater than the current length of the object, the object will increase in length. If the value is smaller, the object will shorten.

DYnamic Option. The DYnamic option allows you to specify the length of an object by dragging it around the screen. When you use this option, you are asked to select an object. AutoCAD will then ask you to specify a new endpoint for the object. You can then drag your cursor around the drawing and dynamically see the length change. To set the length, simply pick a point.

Invalid Objects

When using the LENGTHEN command, it’s possible to ask AutoCAD to create objects that can’t exist or to lengthen objects that cannot be lengthened. For example, although AutoCAD will tell you the length of a closed object like a circle or an ellipse, you can’t add length to a closed object. Another example would be to try to increase the included angle of a line, or to increase the included angle of an arc beyond 360°. In cases such as these, AutoCAD will simply display a message stating that it cannot lengthen the object, and it will ignore the selected object.

Exercise 8-11 Lengthening an Object

Continue from Exercise 8-10.

Start the LENGTHEN command, and select the centerline. AutoCAD replies Current length: 100.0000 and prompts you to Select an object or .

Select the DElta option and enter a value of 25. AutoCAD prompts you to Select an object to change or . Select the bottom portion of each of the vertical lines. Each line is lengthened by 25 units. AutoCAD continues to prompt you to Select an object to change or .

Type F<Enter> to specify a Fence selection. Draw a fence through the three bottom lines (see Figure 8-40), and press <Enter> to end the selection process. AutoCAD will lengthen the three lines by another 25 units.

Save your drawing. Your drawing should resemble Figure 8-41.

Multiple Choice

Circle the correct answer.

1. Copying an object parallel to an existing object is called:

a. Filleting

b. Chamfering

c. Offsetting

d. Extending

2. In a rectangular array, the row distance represents:

a. The horizontal (X) spacing of the arrayed objects

b. The vertical (Y) spacing of the arrayed objects

c. The number of rows in the array

d. None of the above

3. In the TRIM command, when selecting objects to trim, holding down the <Shift> key:

a. Allows you to remove objects from the selection set

b. Puts a 0 radius corner at the intersection of the two objects

c. Allows you to select additional cutting edges

d. Allows you to extend objects to the cutting edges

4. In the FILLET command, when selecting the objects to fillet, holding down the <Shift> key:

a. Allows you to remove objects from the selection set

b. Puts a 0 radius corner at the intersection of the two objects

c. Allows you to select additional cutting edges

d. Allows you to extend objects to the cutting edges

5. In the TRIM command, when asked to select cutting edges, pressing <Enter>:

a. Ends the TRIM command

b. Switches between EXTEND and TRIM

c. Selects all the objects in the drawing as cutting edges

d. None of the above

6. While creating a rectangular array, the array angle:

a. Rotates the array

b. Changes your rectangular array to a polar array

c. Sets the polar array fill angle

d. None of the above

7. When creating a polar array, entering a negative angle to fill:

a. Will copy objects in a clockwise direction

b. Will copy objects in a counterclockwise direction

c. Is not allowed

d. None of the above

8. The BREAK command:

a. Will work on lines and arcs

b. Will work on closed objects

c. Can have the same first and second break point

d. All of the above

9. To convert an arc to a circle:

a. Use the FILLET command with a 0 radius

b. Use the EXTEND command

c. Use the LENGTHEN command

d. Use the JOIN command

10. Breaking an Xline:

a. Creates a line and a ray

b. Creates two rays

c. Converts the Xline to polyline

d. Is not allowed

Matching

Write the number of the correct answer on the line.

True or False

Circle the correct answer.

1. True or False: The OFFSET command cannot be used on closed objects.

2. True or False: Objects must actually touch each other for the TRIM command to work.

3. True or False: The EXTEND command can be used to trim objects.

4. True or False: A fillet radius can be drawn between two parallel objects.

5. True or False: The JOIN command requires that line segments must lie end to end with no gaps or overlaps.

6. True or False: The LENGTHEN command doesn’t work with arcs.

7. True or False: Holding down the <Shift> key during the CHAMFER command allows it to draw fillet curves.

8. True or False: The eRase option of the TRIM and EXTEND commands will undo any changes made during the command.

9. True or False: The BREAK command requires two separate points when breaking a circle.

10. True or False: The BREAK command converts rays into Xlines.

Project 8-1: Classroom Plan, continued from Chapter 7 [BASIC]

1. Open drawing P7-1 from Chapter 7.

2. Draw the remaining equipment and windows shown in Figure 8-42 using the appropriate layers. The windows are all 4′-6″ wide. Do not draw dimensions or text.

   

3. Locate the windows as shown in Figure 8-43. Trim the walls as necessary to allow for the window openings. Change the layout of the desks and chairs to reflect the updated plan.

   

4. Save your drawing as P8-1.

Project 8-2: Optical Mount—English Units [INTERMEDIATE]

1. Start a new drawing using the acad.dwt template.

2. Create the following layers:

   Name	Color	Linetype	Lineweight	Description
   Object	7	Continuous	0.60 mm	Object lines
   Hidden	1	Hidden	0.30 mm	Hidden lines
   Center	2	Center	0.30 mm	Centerlines
   Hatch	4	Continuous	Default	Hatch patterns and fills
   Notes	3	Continuous	0.30 mm	Text and notes
   Dims	2	Continuous	Default	Dimensions

3. Create the three-view drawing as shown in Figure 8-44. Hint: Use the FILLET command to create the round ends of the slots.

   

4. Adjust the LTSCALE system so linetypes appear properly.

5. Do not include notes or dimensions.

6. Save your drawing as P8-2.

Project 8-3: Truss with Soffited Eave Detail [ADVANCED]

1. Start a new drawing using the acad.dwt template.

2. Set linear units to Architectural with precision set to 1/16″.

3. Set angular units to Deg/Min/Sec with precision set to 0d00′00″.

4. Create the following layers:

   Name	Color	Linetype	Lineweight	Description
   A-Detl-Mbnd	1	Continuous	Default	Detail lines that represent material in the background
   A-Detl-Mcut	3	Continuous	0.60 mm	Detail lines that represent material cut in section
   A-Detl-P1	2	Continuous	0.30 mm	Secondary (light) lines
   A-Detl-Batt	1	Batting	Default	Batt insulation
   A-Detl-Pat	1	Continuous	Default	Hatch patterns and fills
   A-Anno-Note	3	Continuous	0.30 mm	Note text
   A-Anno-Title	3	Continuous	0.30 mm	Title text
   A-Anno-Dims	1	Continuous	0.30 mm	Dimensions

5. Draw all line work that appears beyond the section cut as shown in Figure 8-45 on layer A-Detl-Mbnd (roof truss, break lines, vertical wall lines).

   

6. Draw all line work that is cut by the section as shown in Figure 8-45 on layer A-Detl-Mcut (lumber in section, plywood, O.S.B., siding).

7. Draw the X’s that represent lumber in section as shown in Figure 8-45 on layer A-Detl-P1.

8. Do not include notes or dimensions.

9. Save the drawing as P8-3.

Project 8-4: 68-Tooth Rear Sprocket—Metric [BASIC]

1. Start a new drawing using the acadiso.dwt template.

2. Create the following layers:

   Name	Color	Linetype	Lineweight	Description
   Object	7	Continuous	0.50 mm	Object lines
   Hidden	1	Hidden	0.30 mm	Hidden lines
   Center	2	Center	0.30 mm	Centerlines
   Hatch	4	Continuous	Default	Hatch patterns and fills
   Notes	3	Continuous	0.30 mm	Text and notes
   Dims	2	Continuous	Default	Dimensions

3. Draw the sprocket as shown in Figure 8-46 using the appropriate layers. Hint: Draw one sprocket tooth as indicated in Detail A, and array it using the ARRAY command with the Polar option. You can use the same technique to create the holes.

   

4. Adjust the LTSCALE system so linetypes appear properly.

5. Do not include notes or dimensions.

6. Save the drawing as P8-4.

Project 8-5: Residential Architectural Plan, continued from Chapter 7 [ADVANCED]

1. Open drawing P7-5 from Chapter 7.

2. Modify the floor plan as shown in Figure 8-47. Use the TRIM, EXTEND, and FILLET commands to clean up wall intersections and door/window openings. Do not draw dimensions or text.

   

3. Save your drawing as P8-5.