484 Part II Drawing in Two Dimensions

On the	Stmplot stamps a drawing with its name and location, your name, the date, and the time,
CD-ROM	and starts the PLOT command. Look in \Software\Chap17\Stmplot. (AutoCAD only.)

The Batch Plotting Utility has been removed. If you need to plot large numbers of drawings or multiple layouts, use the PUBLISH command, which I cover in Chapter 26. (AutoCAD LT does not have a batch publishing feature.)

Summary

In this chapter, you read how to lay out and plot a drawing. You discovered how to:

Lay out a drawing in model space

Use a paper space layout

Create layouts, using the Layout Wizard and using the commands individually

Use the Page Setup dialog box to specify layout settings

Create and apply plot styles

Plot a drawing

This chapter ends Part II, “Drawing in Two Dimensions.” Part III, “Working with Data,” explains how to integrate your drawing with data about your objects. The next chapter explains how to use blocks and attributes.

Working with Data

Part III covers the various ways you work with data in your drawings. This part brings you to a new level of sophistication in

terms of automation and interfacing with other drawings and data. Chapter 18 covers blocks and attributes, which enable you to work repetitively with objects and text. You can use attribute text to create a simple database of information related to your objects. Chapter 19 explains how to refer to other drawings with external references, also called xrefs. Chapter 20 describes how to connect sophisticated external databases to objects in your drawings.

P A R T

III

In This Part

Chapter 18

Working with Blocks and Attributes

Chapter 19

Referencing

Other Drawings

Chapter 20

Working with External Databases

Working with Blocks and Attributes

As you draw, you’ll find that you often need to place the same group of objects several times in a drawing. An architect needs to

place windows and doors many times in a plan layout of a house. An electrical engineer places electrical symbols in a drawing again and again. A mechanical model may include nuts, bolts, and surface finish symbols many times in a drawing. Blocks are groups of objects that you save and name so that you can insert them in your drawing whenever you need them. A block is one object regardless of the number of individual objects that were used to create it. Because it’s one object, you can easily move, copy, scale, or rotate it. However, if necessary, you can explode a block to obtain the original individual objects.

One advantage of blocks is that they reduce the size of the drawing file. A drawing stores the composition of a block only once, along with a simple reference to the block each time it’s inserted, instead of storing each individual object in each block in the drawing database.

As soon as you have a block in a drawing, you can work with it as with any other object. You can snap to object snaps of the individual objects within blocks as well as trim and extend to objects within blocks, even though you can’t edit the individual objects. For example, you can draw a line from the midpoint of a line in a block.

Many disciplines use parts libraries that may consist of thousands of items. You use the block feature to save and insert these parts. You can save many blocks in a drawing or place each in a separate file so that you can insert them in any drawing you wish.

You can attach attributes to blocks. Attributes are labels that are associated with blocks. Attributes have two main uses — to label objects and to create a simple database. If you have AutoCAD, you can use the new field feature in your attributes. (Chapter 13 explains all about fields.)

This chapter explains how to make the most of blocks and attributes.

Combining Objects into Blocks

Any object or set of objects can be saved as a block. Creating a block is easy, but a little planning makes using it much simpler. Before you create a block you need to understand how blocks are inserted and how you want to use the specific block that you’re creating.

18C H A P T E R

In This Chapter

Combining objects into blocks

Saving blocks as drawing files

Inserting blocks and files into drawings

Managing blocks and parts libraries

Using Windows features

Working with attributes

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Understanding base points and insertion points

Figure 18-1 shows the legend for a plat drawing. Each legend symbol is a block that is then inserted in the drawing as needed. The first symbol has been selected, and you can see that it has one grip at the base point. The base point is the point you use to insert the block. Every block must have a base point. When you insert the block, the base point is placed at the coordinate you specify for inserting the block — the insertion point. All the objects of the block are then inserted in their proper place relative to that insertion point.

The base point does not have to be on the object, but it should be in a location that makes it easy to insert the block. Figure 18-2 shows a different sort of block — a title border/block. In this case, the base point is usually inserted at 0,0 of the drawing. By placing the base point at the lower-left corner of the border, you can easily place this block in any drawing. The base point is similar in concept to the justification point on text objects.

Block

Base point

Figure 18-1: Each legend symbol is a block. Every block has a base point.

Figure 18-2: This block is a title block. Its base point is at the lower-left corner.

Block

Base point

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Creating a block

To create a block, first create the objects just as you want to save them. You may include other blocks as objects in your block. (A block within a block is called a nested block.)

After you’ve created the objects for your block, follow these steps:

1.Choose Make Block from the Draw toolbar to start the BLOCK command and open the Block Definition dialog box, shown in Figure 18-3. The dialog box guides you

through the process of defining a block.

2.In the Name text box, type a name for the block (up to 255 characters; spaces allowed).

3.Click Select Objects. You return to your drawing temporarily. Use any selection method to select the objects you want in your block. Press Enter to end selection and return to the Block Definition dialog box. (If you select the objects before starting the command, you skip this step. The dialog box notes how many objects are selected.) To filter out the selected objects, choose Quick Select (described in Chapter 10).

4.Choose a base point. By default, the base point is 0,0 (or 0,0,0 for 3D drawings). To define any other point, such as an object snap on any of the objects in the block, click Pick Point. You return to your drawing temporarily. At the Specify insertion base point: prompt, specify a point, which returns you to the dialog box.

Caution	For precision, you should always use an object snap when defining the base point. If the
	base point you need to use is not on any object, you can use the From object snap, tracking,
	or some other means of specifying a precise coordinate.

5.Choose how you want the objects of the block to be treated:

•If you want to keep the objects that you selected as individual objects, check Retain.

•If you created the objects to insert them elsewhere and do not need the original objects, check Delete.

•To convert the objects to a block, check Convert to Block.

Figure 18-3: The Block Definition dialog box.

490 Part III Working with Data

6.By default, a block includes an icon based on the block. If you later use the DesignCenter to insert the block in another drawing, this icon will appear in the preview box to help you decide which block you want to insert. Click Do Not Include an Icon if you don’t want one.

7.Choose the insert units you want to use when defining your block. (You can choose anything from microns to parsecs!) Let’s say you work in kilometers and save a block with an insert unit of kilometers. When you insert a block, it will be measured in kilometers, rather than millimeters or inches. If the units aren’t important to you, you can specify the units as Unitless.

8.If you want, enter a description for the block. As with the icon described in Step 6, the description is used by the DesignCenter. You can also add a hyperlink by clicking the Hyperlink button. (See Chapter 28 for more on hyperlinks.)

9.Click OK to return to your drawing.

The definition of the block is now stored in the drawing, ready for you to insert as many times as needed. If you checked Delete, your objects disappeared. You can retrieve them by the one command with a sense of humor — OOPS. OOPS restores the last object or set of objects you erased — whether by using the ERASE command or by creating a block, even if you used some other command in the meantime. By contrast, UNDO undoes almost all commands, but only in the order they were executed.

Tip	If you create a number of block definitions that you don’t end up using in the drawing, use the
	PURGE command to delete them. This reduces the size of the drawing file.

Redefining a block

One advantage of deleting the objects is that their disappearance confirms that you selected the right objects. If you make a mistake, or if you want to change the block in some way, you can redefine it. If you just created the block, use UNDO and make any necessary changes. If you created the block earlier, follow these steps:

1.Insert the block and explode it. (Exploding is covered later in this chapter.)

2.Make the desired changes and repeat the process of defining the block, using the same name for the block.

Caution	When you specify the name of the block, you should type it, rather than choose it from the
	Name drop-down list. Choosing the name from the list replaces selected objects (that you
	wanted to be in the new version of the block) with the objects from the previous block defi-
	nition and sets the insertion point to 0,0.

3. Click Yes when the message asks if you want to redefine the block.

Redefining a block that has been inserted in your drawing updates all the blocks. This is a powerful technique to control your drawing. If you have repetitive symbols in your drawing, it’s worthwhile to make blocks out of them just so that you can make this type of global change if necessary.

On the	The drawing that you need for the following Step-by-Step exercise on creating a block, ab18-
CD-ROM	a.dwg, is in the Drawings folder on the CD-ROM.

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STEP-BY-STEP: Creating a Block

1.Open ab18-a.dwg from the CD-ROM.

2.Save the file as ab18-01.dwg in your AutoCAD Bible folder. This is a small portion of an electrical schematic drawing, as shown in Figure 18-4. OSNAP should be on. Set running object snaps for endpoint, quadrant, and intersection.

Figure 18-4: A portion of an electrical schematic.

1

3. To make a block of the 1.5 amp fuse, choose Make Block from the Draw toolbar.

4.In the Name text box of the Block Definition dialog box, type 1-5 amp fuse.

5.Click Select objects to return to the drawing temporarily.

6.Select the boxed objects shown in Figure 18-4 (the two lines of text, the two circles, and the two arcs). Press Enter to end selection and return to the dialog box. Under the Select Objects button, the dialog box displays 6 objects selected.

7.Click Pick Point in the Base Point section of the dialog box.

8.In the drawing, use the Quadrant object snap to pick 1 in Figure 18-4.

9.In the dialog box, check Delete. Create Icon from Block Geometry should be checked. The Insert Units should be Unitless. Leave the Description blank. Click OK to return to your drawing. This action erases the objects that made up the block.

10.To check that the block has been created, choose Make Block from the Draw toolbar. Click the Name drop-down arrow to see your block. Click Cancel.

11.Save your drawing.

Saving blocks as files

You can use the DesignCenter to insert blocks from any drawing. Nevertheless, many users need to organize their blocks in their own files so they can be easily stored and located. Parts and symbols libraries are made up of many individual drawing files, one for each part or symbol. Such libraries are a powerful aid to drawing more efficiently.

To save a block as a file, follow these steps:

1.Type wblock . (WBLOCK stands for write block. Writing to a file is another expression for saving to a file.)

2.In the Write Block dialog box, shown in Figure 18-5, choose the location (drive and folder) for the file.

492 Part III Working with Data

Figure 18-5: Use the Write Block dialog box to save a block as a separate drawing file.

3.In the Source section, choose how you want to create the drawing file:

•Block: Use this option when you’ve already created the block and now want to save it as a drawing file. Choose the block from the drop-down list.

•Entire drawing: Use this option to make a copy of your drawing.

•Objects: Use this option to start defining the block in the same way you define a block within a drawing. The Base Point and Objects sections become available.

4.In the File Name and Path text box, type the path and name of the file you want to create. (You can also click the ellipsis button to navigate to a location and then type a filename in the Browse for Drawing File dialog box. Click Save to return to the Write Block dialog box.) If you’ve already created the block in your drawing, you should generally use the same name as the block to avoid confusion, but you might have special naming conventions for a block library.

5.In the Insert Units drop-down list, choose the units you want for your block or choose Unitless for no units.

6.After you’re done, click OK to create the drawing file.

Tip	When you save a drawing that you plan to insert as a block, use the BASE command to create
	the insertion point. By default, the base point is 0,0,0. By setting the base point to another
	point in the drawing, such as an object snap on one of the objects, you can control how that
	drawing is inserted.

Replacing an existing file

If you make a mistake when selecting objects to write to a file with WBLOCK, or want to change the objects in the file, you can replace the file. Start WBLOCK and type the name of the block file you want to change. Be sure to choose the same file location. When you click OK, a message asks if you want to replace the existing file. Click Yes.

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On the	The drawing that you need for the following Step-by-Step exercise on saving a block to a file,
CD-ROM	ab18-b.dwg, is in the Drawings folder on the CD-ROM.

STEP-BY-STEP: Saving a Block to a File

1.Open ab18-b.dwg from the CD-ROM.

2.Save the file as ab18-02.dwg in your AutoCAD Bible folder. This is a large title block, as shown in Figure 18-6. OSNAP should be on. Set a running object snap for endpoint.

1

Figure 18-6: A title block can be saved as a file and inserted into any other drawing.

3.Type wblock . In the Source section of the Write Block dialog box, click Entire drawing. Set the File Name and Path box to AutoCAD Bible\tb-f by typing the path and the filename. (Alternatively, click the ellipsis [...] button and navigate to your AutoCAD Bible folder. In the File Name text box, type tb-f. Click Save.) Click OK.

4.Press Enter to repeat the WBLOCK command.

5.In the Source section of the dialog box, choose Objects. In the Objects section, click Select Objects.

6.Use Zoom Window to zoom in on the text at the bottom-right corner of the title block. At the Select objects: prompt, select all the 90° rotated text at 1 in Figure 18-6. Press Enter to end selection.

7.In the Base Point section, click Pick Point. Use the Endpoint object snap to pick the bottom-left corner of the box containing the text you selected. Using this base point lets you easily place the text in the box at any time.

8.In the Object section, choose Delete from Drawing.

9.In the File Name and Path text box, type notes-tol after the path, which should already be set to your AutoCAD Bible folder. Click OK to save the block as a file.

10.Type oops to bring back the text.

11.Choose Zoom Extents from the Zoom flyout of the Standard toolbar. Save your drawing.