like the chameleon changing color to match its surroundings or a politician changing his position to match the day’s opinion polls.
2. Click the Insert Block button on the Draw toolbar.
The Insert dialog box appears, as shown in Figure 13-3.
Figure 13-3: The Insert dialog box.
3. Enter the block definition name or external filename by using one of the following methods:
• Use the Name drop-down list to select from a list of block definitions in the current drawing.
• Click the Browse button to select an external DWG file and have AutoCAD create a block definition from it.
You can use an external drawing to replace a block definition in your current drawing. If you click Browse and choose a file whose name matches the name of a block definition that’s already in your drawing, AutoCAD warns you and then updates the block definition in your drawing with the current contents of the external file. This process is called
4. Enter the insertion point, scale, and rotation angle of the block.
You can either click the Specify On-Screen check box in each area, to specify the parameters on-screen at the command prompt, or type the values you want in the Insertion Point, Scale, and Rotation text boxes.
Check the Uniform Scale check box to constrain the X, Y, and Z scaling parameters to the same value (which in almost all cases you want).
5. If you want AutoCAD to create a copy of the individual objects in the block instead of a block insert that points to the block definition, click the Explode check box.
6. Click OK.
7. If you checked Specify On-Screen for the insertion point, scale, or rotation angle, answer the prompts on the command line to specify these parameters.
After you insert a block, all the objects displayed in the block insert behave as a single object. When you select any object in the block insert, AutoCAD highlights all the objects in it.
Another way to insert a block is to drag a DWG file’s name from Windows Explorer and drop it anywhere in the current drawing window. AutoCAD then prompts you to choose an insertion point and optionally change the default scale factor and rotation angle. Similarly, you can drag a block definition’s name from the Blocks section of the DesignCenter palette and drop it into the current drawing window. (Chapter 4 describes DesignCenter.)
AutoCAD provides one additional way of inserting blocks: the Tool Palette, which is described in Chapter 2. As is true of using Tool Palette for hatching (Chapter 11), you first must create and configure appropriate tools — that is, swatches. The easiest method is right-clicking a drawing in DesignCenter and choosing Create Tool Palette. A new page is added to the Tool Palette area containing all the block definitions from the drawing that you right- clicked. Simply click and drag a tool to insert its corresponding block into a drawing. As with hatching, you don’t get the chance to specify a different insertion scale. You also can’t use all of AutoCAD’s precision tools to specify the insertion point precisely, so you may need to move the block into place after inserting it. I recommend that you first master the other block insertion methods described in this chapter — especially the Insert dialog box and DesignCenter palette. Then if you find yourself inserting the same blocks frequently, consider creating a Tool Palette containing them. See “tool palettes, adding drawings from” in the AutoCAD online help system for more information.
Be careful when inserting one drawing into another. If the host (or parent) drawing and the inserted (or child) drawing have different definitions for layers that share the same name, the objects in the child drawing takes on the layer characteristics of the parent drawing. For example, if you insert a drawing with lines on a layer called Walls that’s blue and dashed into a drawing with a layer called Walls that’s red and continuous, the inserted lines on the wall layer will turn red and continuous after they’re inserted. The same rules apply to linetypes, text styles, dimension styles, and block definitions that are nested inside the drawing you’re inserting.
If you need to modify a block definition after you’ve inserted one or more instances of it, use the REFEDIT command (Modify>Xref and Block Editing>Edit Reference In-Place). Look up “REFEDIT” in the AutoCAD online help system.
You may think of attributes as the good (or bad) qualities of your significant other, but in AutoCAD, attributes are fill-in-the-blank text fields that you can add to your blocks. When you create a block definition and then insert it several times in a drawing, all the ordinary geometry (lines, circles, regular text strings, and so on) in all the instances are exactly identical. Attributes provide a little more flexibility in the form of text strings that can be different in each block insert.
For example, suppose that you frequently designate parts in your drawings by labeling them with a distinct number or letter in a circle for each part. If you want to create a block for this symbol, you can’t simply draw the number or letter as regular text using the mText or TEXT command. If you create a block definition with a regular text object (for example, the letter A), the text string will be the same in every instance of the block (always the letter A). That’s not much help in distinguishing the parts!
Instead, you create an
The AutoCAD documentation and dialog boxes often use the term
If you’ve worked with databases, the correspondences in Table 13-1 between AutoCAD objects (blocks and attributes) and database terminology may help you understand the concept.
Table 13-1 Attribute and Database Comparison
| AutoCAD | Database |
|---|---|
| block definition | database table structure |
| block insert | one record in the table |
| attribute definition | field name |
| attribute value |
