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AutoCAD prompts:

Hide for current state or all visibility states [Current/All] <Current>: C

11.Click Visibility States again and then click New to create a new visibility state. In the New Visibility State dialog box, enter a descriptive name. Select the Show All Existing Objects in New State radio button and then click OK.

All your geometry should reappear.

12.Repeat Steps 9 and 10 to create additional visibility states associated with the remaining geometry or blocks.

The geometry or block insert associated with the last created visibility state should be visible onscreen.

13.Click OK to close the Visibility States dialog box, and then click Close Block Editor on the Ribbon. Save the changes to your new block or to Current Drawing.

AutoCAD displays an alert box asking whether you want to save changes to your block. Click Cancel to return to the block editor or Discard the Changes to close the Block Editor without saving your changes. Click Save the Changes to update the block and exit. AutoCAD closes the block authoring environment and returns to the standard drawing editor window.

The Block Editor tab includes a Test Block tool you can use to see what your finished product will look like without the hassle of closing the editor and inserting or manipulating the block inside the drawing editor. Test Block displays the geometry and lets you try different parameters; then you can easily return to the Block Editor to tweak your masterpiece. You’ll find the Test Block button on the Open/Save panel of the Block Editor contextual tab.

Lights! Parameters!! Actions!!!

You can modify the appearance of individual instances of the same block by defining parameters and actions to move, rotate, flip, or align parts of them. You can adjust the block’s appearance while you insert it or at any time afterward. The following steps show you how to use the Block Editor to add some action to a block definition:

1.Open a drawing that contains some block definitions whose appearance you’d like to spice up a little, or draw some simple geometry that might make a suitably dynamic block.

Action parameters are most effective in block definitions that contain groups of related objects — for example, an office desk and chair or a furniture arrangement.

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418 Part IV: Advancing with AutoCAD

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

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

4.Create some geometry or insert some blocks.

When you insert blocks, make sure that the Explode check box at the lower-left corner of the Insert dialog box is not selected, and then click OK.

Draw the geometry or insert the blocks in a group so that you can insert the finished arrangement into your drawings. For example, upcoming Figure 18-10 shows the creation of a dynamic block for a coffee shop or cafeteria.

5.Repeat Step 4 until you’ve drawn all the needed geometry or inserted all the necessary blocks.

6.Click the Parameters tab of the Block Authoring Palettes and then click Rotation Parameter.

AutoCAD prompts you to specify the parameter location.

7.Click to place the parameter marker somewhere on the object geometry other than the base-point location.

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.

8.AutoCAD places a parameter marker at the selected point and returns to the command line, prompting you to specify the radius of the rotation parameter and the default rotation angle.

The parameter marker’s label appears next to the rotation parameter marker.

9.Click the Actions tab of the Block Authoring Palettes and then click Rotate. Select the Rotate Parameter, select the objects that should be modified when the grip is used, and specify a point for the action’s label.

AutoCAD returns to the command prompt. At this point, it’s fine to go with default values and onscreen pick points.

10.Repeat Steps 6 through 9, trying different parameters and actions.

For example, choose a Point Parameter and a Move Action.

Figure 18-10 shows a set of block components, several of which have action parameters assigned. After the block is inserted, you can manipulate the components to which you’ve added parameters to vary the appearance of the blocks. We explain how a little later in this chapter.

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Chapter 18: Everything from Arrays to Xrefs 419

Figure 18-10: A passel of parameters ready for action.

11.Click Close Block Editor on the Ribbon and save or discard your changes.

AutoCAD closes the block-authoring environment and returns to the standard drawing editor window.

Manipulating dynamic blocks

After a dynamic block is inserted in a drawing, you can select it and modify its display through a special set of custom grips. (That’s what AutoCAD calls them, so I’m following suit.)

When you select a nondynamic block, you see a single grip at the insertion point. When you select a dynamic block, you see at least two — and maybe more — custom grips, as well as the insertion point grip. The custom grips usually look different from the regular object grips, but not always, so be careful while clicking grips.

The following steps show you how to make your dynamic blocks do the things you just spent all this time teaching them to do:

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420 Part IV: Advancing with AutoCAD

1.Insert a few blocks that contain some dynamic parameters, such as visibility or action parameters.

If your block inserts don’t have any action parameters, go to Step 4.

2.Select a block that includes some action parameters.

The block insert displays a number of grips (see Figure 18-11). If the insert displays only a single square grip, it isn’t a dynamic block.

Figure 18-11: Variations on dynamic blocks (original on the right, and a handy grip tip on a chair at left center).

3.Click one of the custom grips — for example, clicking a round grip opens the rotation parameter of the object. Rotate the component as required.

4.Select a block that includes a visibility parameter and then click the visibility grip. Choose the desired visibility state from the menu that appears.

For additional information on manipulating actions and visibility states, look up Dynamic Blocks in the online help system.

Dynamic blocks, as we suggest more than once, are a powerful — and complicated­ — feature. Prior to AutoCAD 2010, the Block Authoring Palettes contained 10 selectable parameters, 8 actions, and 20 parameter sets. AutoCAD 2010 added 12 geometric constraints and 6 dimensional constraints. We could write a book on the topic. Until we do, AutoCAD’s online help system is your best resource for more information on all the possibilities of dynamic blocks. The quickest and most direct way to AutoCAD’s own help on the subject is to type Dynamic Blocks into the Search box on the program title bar.

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19

Call the Parametrics!

In This Chapter

Introducing parametric drawing

Understanding constraints

Applying geometric and dimensional constraints

Using inferred constraints

Editing parametric drawings

Afew releases back, AutoCAD included a set of parametric drawing tools, and, offhand, we can’t think of a more significant new feature in recent

years. (Don’t worry; we’re going to offer a definition of parametric in just a few more paragraphs.) In fact, if you work primarily in 2D — and especially if you’re in the manufacturing business — parametrics in AutoCAD

(and, to a very limited degree, in AutoCAD LT) might just be the most significant new feature ever since the beginning of engineering drawings in Roman times.

If you know what we’re talking about, you’re probably pretty interested in finding out more about what

you can do with parametrics in AutoCAD. If, on the other hand, you think parametrics are the folks who show up when you dial 911, the following paragraphs should straighten you out.

Imagine this. Your boss has been in a meeting all morning with an important client. At two minutes before noon, they emerge. Your boss hands you a marked-up print and rather imperiously commands, “We need these 12 dimensions changed and the drawing

updated by the time we get back from lunch.” The drawing involves multiple views, several cross sections, and a couple of details at different scales.

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