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Figure 18-7: The Attach PDF Underlay dialog box.

AutoCAD allows you to import about 20 different file formats into an AutoCAD drawing. Most of these are 3D modeling formats. They are imported into model space (not attached or xref-ed), and are used as the basis for additional 3D modeling and editing and/or for generating 2D working drawings from them. We discuss 3D to 2D in Chapter 23.

Theme and Variations: Dynamic Blocks

You can add variety to your blocks by making them dynamic. The two most useful applications for dynamic blocks are multiple presentations of similar objects and manipulation of components within individual block inserts.

AutoCAD dynamic blocks feature offers you a great deal of flexibility to block creation and insertion, but using them is also a very complicated system with its own set of commands and system variables. We recommend that you become very familiar with regular block creation and insertion techniques for creating and inserting blocks (which we describe in Chapter 17) before you tackle dynamic blocks.

Spend some time planning your dynamic blocks. Sketch out the geometry for each variation in appearance (visibility state) and decide where the common base point should be. Unless you’re a lot smarter than we are, you’ll probably find that creating dynamic blocks is complex enough without trying to design your blocks as you go.

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414 Part IV: Advancing with AutoCAD

Now you see it

If your drawing shows six different kinds of windows, one approach is to create six different standard blocks to represent them all. Alternatively, you can create a single dynamic block and define visibility states to cover all six different types. The following steps show you how to make your blocks do double (or sextuple?) duty by using the Edit Block Definition dialog box:

1.Open a drawing that contains some block definitions you’d like to combine, or draw some simple geometry to make some similar types of objects.

You can find the files we use in this sequence of steps at this book’s companion website. Go to www.dummies.com/go/autocad2013fd and download afd18.zip. The drawing named afd18b.dwg contains the three-piece furniture suite (see Figure 18-8) we use to create a dynamic block.

You can create dynamic blocks from scratch, or you can work with existing standard (nondynamic) block definitions. Figure 18-8 shows a drawing with three nondynamic blocks.

2.On the Block panel of the Home tab, choose Block Editor to open the Edit Block Definition dialog box.

3.In the Block to Create or Edit box, specify a new block name or select Current Drawing and then click OK to display the Block Editor window.

The Block Editor is a special authoring environment with its own Ribbon tab plus a passel of command-line commands. You also have access to the rest of the Ribbon tabs, so you can draw and edit just like you would in the regular drawing window. The background color is different from the drawing editor’s background color to help you remember where you are.

The Block Editor tab’s Geometric, Dimensional, and Manage panels (see Figure 18-9) are elements of the AutoCAD parametric drawing feature. (AutoCAD LT doesn’t fully support parametric drawing, so the LT Block Editor lacks the Geometric and Dimensional panels and gets a miniversion of the Manage panel.) In this book, we don’t have room to cover parametric constraints in dynamic blocks, but we do cover parametric drafting in Chapter 19. The concepts are pretty similar to adding parametric features to dynamic blocks.

If you enter a new block name, AutoCAD displays an empty blockauthoring environment where you draw geometry or insert existing blocks. If you instead select Current Drawing, AutoCAD places all drawing objects inside the block authoring environment.

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Figure 18-8: Three blocks to make three seats.

4.Create some geometry for the first visibility state. Alternatively, click the Home tab, choose Insert on the Block panel, and select an existing block definition to serve as the first visibility state.

When creating geometry from scratch, pay attention to where the common base point should be. Although you use different blocks to assemble a multiple-view block, they should all have the same base point. (0,0 is a good one for blocks.) You don’t want your chairs jumping around between different insertion points!

5.If you inserted an existing block in Step 4, deselect all three Specify On-Screen check boxes, make sure that the Explode check box is not selected, and then click OK.

6.Repeat Steps 4 and 5, drawing or inserting all the necessary geometry.

At this point, your drawing screen may look pretty strange (see Figure 18-9). Don’t worry; you’re going to fix it in the next steps.

7.Click the Parameters tab of the Block Authoring Palettes and then click Visibility, as shown in Figure 18-9.

If the palettes aren’t open, click Authoring Palettes on the Manage panel on the highlighted Block Editor contextual tab of the Ribbon.

AutoCAD prompts you to specify the parameter location.

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416 Part IV: Advancing with AutoCAD

Visibility Status controls

Block Editor panels

Block Authoring palettes Visibility Parameter marker

Figure 18-9: Three seats in the Block Editor.

8.Click to place the parameter marker somewhere other than the base point location you chose in Step 4.

AutoCAD places a parameter marker at the selected point and returns to the command line. As shown in Figure 18-9, the label Visibility1 appears next to the Visibility Parameter marker, and a yellow Alert symbol indicates that no action has been assigned to the parameter yet. The controls on the Ribbon’s Visibility panel become active.

The parameter location that you specify will be the spot on the block where the dynamic block option grip will be displayed. It’s not crucial where you locate this point, but try to pick a sensible location on the object. If you specify the same point for the parameter location as the base point for the block, you may have a hard time selecting the dynamic option grip.

9.Click Visibility States on the Visibility panel. Click Rename and change VisibilityState0 to something more descriptive. Then click OK.

As is the case with other named objects in AutoCAD, best practice is to assign useful, descriptive names rather than accept the default generic labels.

10.On the Visibility panel, click the Make Invisible button. At the Select Objects prompt, select the geometry or block inserts that should be invisible in the current visibility state — that is, those that are not associated with the current visibility state — and then press Enter.

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