Before you start to add dynamic block features to blocks, you'll want to get familiar with the Block Editor. The Block Editor offers an easy way to make changes to existing blocks, and as you'll see a bit later, it's also the tool you'll use to give your blocks some additional capabilities.

As an introduction to the Block Editor, you'll make changes to the now-familiar unit plan from earlier tutorials. Start by editing the Kitchen block in the unit:

The gray background tells you that you're in the Block Editor. You'll also see the Block Editor tab along the top of the drawing area and the Block Authoring palettes, as shown in Figure 18.2.

Figure 18.2. The Block Editor and its components

Take a moment to look over the panels and tools on the Block Editor tab. This tab offers several housekeeping tools that let you open, save, and exit the Block Editor. You can point to each tool in the tab's panels to see its description. Figure 18.3 shows the Block Editor tab and tools.

Figure 18.3. The Block Editor tab

Both the Block Editor tab and the Block Authoring palettes offer tools for adding dynamic block features that you'll explore later in this chapter. You may notice that the Block Editor tab contains the geometric and dimensional constraint panels that you learned about in Chapter 17. Let's continue our look at the basic features of the Block Editor.

Editing a Block and Creating New Blocks

The Block Editor lets you edit a block using all the standard AutoCAD editing tools. In the following exercise, you'll modify the kitchen sink and save your changes to the drawing:

1. Delete the rectangle that represents the sink in the kitchen block.

2. Click Close on the Block Editor tab's Close panel (see the right end of Figure 18.3).

3. A message appears asking if you want to save your changes to the Kitchen block. Click Save The Changes. Your view returns to the standard AutoCAD drawing area, and you can see the changes you made to the kitchen, as shown in Figure 18.4.

Figure 18.4. The unit plan with the edited Kitchen block

As you can see, editing blocks with the Block Editor is simple and straightforward. In this example, you deleted part of the block, but you can perform any type of drawing or editing to modify the block. The Block Editor tab also offers other block-saving options in its panels. You can save the block as you work by clicking the Save Block Definition button. If you need to create a variation on the block you're currently editing, you can click the Save Block As tool on the Block Editor's expanded Open/Save panel to create a new block or overwrite an existing one with the drawing that is currently in the Block Editor.

If you want to edit a different block after editing the current one, you can click the Save Block tool on the Block Editor's Open/Save panel to save your current block and then click the Edit Block tool.

This tool opens the Edit Block Definition dialog box that you saw earlier. You can then select another block to edit or create a new block by entering a name for your block in the Block To Create Or Edit input box.

Now that you've seen how the Block Editor works, you can begin to explore the creation of dynamic blocks. As an introduction, you'll create a rectangle that you'll use to replace the sink in the kitchen. You'll add a dynamic block feature that will allow you to adjust the width of the sink using grips. In addition, you'll add a control that limits the size to one-unit increments.

Start by creating a block from scratch using the Block Editor:

You could save this block now and you'd have a simple, nondynamic block. Next, you'll add a couple of features called parameters and actions. As their names imply, parameters define the parameters, or limits, of what the dynamic block will do, and actions describe the particular action taken when the grips of the dynamic block are edited. For example, in the next section, you'll add a Linear parameter that tells AutoCAD that you want to restrain the grip editing to a linear direction. You'll also add a Stretch action that tells AutoCAD that you want the grip edit to behave like a Stretch command that pulls a set of vertices in one direction or another.

Figure 18.5. The rectangle for the Sink block

Adding a Parameter

The first parameter you'll add establishes the base point for the block. This will let you determine the point used when inserting the block in your drawing:

1. In the Block Authoring palettes, select the Parameters tab.

2. Click the Base Point Parameter tool, Shift+right-click, select the Endpoint osnap, and then click the lower-left corner of the rectangle. This is how you determine the base point or insertion point of a block while using the Block Editor.

   

Next, you'll add a parameter that will determine the type of editing you want to add to the block. In this case, you want to be able to grip edit the width of the block. For that you'll use the Linear Parameter tool.

1. 

2. At the prompt

   Specify start point or [Name/Label/Chain/Description/Base/Palette/Value set]:

   Shift+right-click and select the Midpoint osnap; then select the left side of the rectangle.

3. Shift+right-click again, select Midpoint from the Osnap menu, and select the right side of the rectangle.

4. At the Specify label location: prompt, the parameter name appears with the parameter label at the cursor. Click below the rectangle to place the label as shown in Figure 18.6.

Figure 18.6. Placing the Linear parameter

The parameter you just added lets you modify the block in a linear fashion. In this case, it will allow you to change the width of the rectangle. As you'll see, the locations of the parameter's arrows later become the grip locations for the dynamic block.

But just adding the parameter doesn't make the block dynamic. You need to include an action before a parameter can be used. You may have noticed the warning symbol in the parameter you just added. It tells you that you need to take some further steps to make the parameter useful.

Adding an Increment Value

You can grip edit your dynamic Sink block to modify its width, and as you saw in the previous exercise, you can enter a specific value for the width as well. But suppose you'd like to limit grip movement so that the sink only changes in 1″ increments. Or you might have a dynamic block representing a bolt, and you want the bolt length to increment in 1/16-inch steps.

You can set parameters to have an increment value so that grip edits are limited to a specific distance. The following steps show how you can set up the Linear parameter of the Sink block so the sink width can be grip edited to 1″ increments:

1. Double-click the Sink block. Then, in the Edit Block Definition dialog box, make sure Sink is selected and click OK.

2. Click the Linear parameter's Distance1 label, right-click, and choose Properties.

3. In the Properties palette, scroll down to the Value Set group and click the Dist Type listing. The Dist Type option changes to a drop-down list.

4. Expand the list and select Increment.

   

5. Click in the Dist Increment input box just below the Dist Type options, and enter 1 for an increment distance of 1 inch.

   

6. Close the Properties palette, and then click Close on the Block Editor tab's Close panel.

7. Save the Sink block.

8. Click the Sink block to expose its grips.

9. Click and drag the right arrow grip to the left. As soon as you click the grip, you see a set of increment marks appear indicating the increment steps for the grip. As you move the grip, the sink width jumps to the increment marks, which are 1 inch apart, as shown in Figure 18.8.

10. Set the width of the sink back to 12 inches.

Figure 18.8. Grip editing the Sink block with the Linear parameter's increment value set to 1

In addition to an increment distance, you can set a range of movement for the Linear parameter. You may have noticed the minimum and maximum input boxes in the Properties palette in steps 4 and 5. You can enter values for these settings that define the range of movement allowed for the grip edits.

Understanding the Cycling Option

You can turn on the Cycling option in the Misc group of the Properties palette of any parameter grip. Cycling allows you to use the parameter grip as an insertion point. With this option turned on, you can press the Ctrl key to cycle between the standard insertion point and the cycle-enabled grip of a parameter while inserting the block.

The sink exercise is a simple demonstration of how you can create and use dynamic blocks. But as you can see from the Block Authoring palettes, you can add many other parameters and actions to a block.

Editing Parameters and Actions

In the previous exercises, you inserted parameters and actions using the default settings. These settings give you default names and labels for the parameters and actions, but you can always change them later. To change the label that appears for a parameter, double-click the label. The label will then appear in a rectangular box, showing you that you can change its text.

If you want to include additional objects for an action, click the action icon to select it, and then right-click and select Action Selection Set

In the sink example, you added two Stretch actions to a Linear parameter. This enabled the block to be stretched in both the left and right directions. The actions and parameters offer one way of creating dynamic blocks, but you can also use the geometric and dimensional constraints that you were introduced to in the previous chapter.

In this section, you'll turn a simple door block into a dynamic block that will allow you to resize the door to any opening. In the process, you'll learn how to apply geometric and dimensional constraints to create a dynamic block.

At first, you may think that all you need to do to resize a door would be to change the scale. But when you scale the door, all its features, including the door width, are scaled proportionally. To really be accurate, you only want to stretch the door width and scale the door swing, leaving the door thickness at the same dimension. This can be accomplished by adding two aligned dimensional constraints and a few geometric constraints to the door.

Start by opening the Door block in the Block Editor and adding the geometric constraints to the door:

Figure 18.10. Select the rectangle representing the door.

The geometric constraints will make sure that the door maintains its rectangular shape when you apply changes to the door through the dynamic block feature. The constraints used are parallel, tangent, and horizontal. You'll need to add a constraint to keep the arc connected to the rectangle.

The coincident constraint you just added will keep the arc and rectangle connected at the bottom-right corner of the rectangle.

Next, add a dimensional constraint. Most likely, you'll need to scale the door based only on the door opening, so place a dimensional constraint between the door hinge and the end of the door swing arc:

Figure 18.12. The aligned dimensional constraint applied to the door opening

Notice that the constraint you just added is named d1. This will be an important feature in the next two constraints that you add.

Next, add another dimensional constraint to the width of the door rectangle. This time, you want the constraint to follow the door opening constraint, so instead of accepting the default value for the dimension, you'll enter the name of the first dimensional constraint:

Finally, add the dimensional constraint for the arc:

Now try out your new dynamic block by adjusting the door size:

Notice that, although you were able to enter a door dimension directly to the block, you didn't change the door thickness when the door size changed. Only the door swing and width changed to accommodate the new door size. This is most apparent if you scale the door to a small size such as 6″ or 12″.

Earlier, you saw how you can add an increment value set to make a dynamic block stay in a set range of sizes. You can also set up a dynamic block to offer a range of sizes in a pop-up list. To do this, you need to employ the Block Table feature.

In the following exercise, you'll add a selectable list to the Door block to allow the door size to be selected from a list. Start by adding the block table that will allow you to set up a set of predefined door dimensions.:

Now you can select from the door sizes in a pop-up list:

Figure 18.20. Selecting a door size from a list

If at a later time you need to make changes to the list or add more dimensions, you can open the block in the Block Editor and then click the Block Table tool. The Block Properties Table dialog box will appear with the data you entered earlier. You can then make changes to the table.

In this example, you saw that you can easily add predefined sizes to the dimensional constraint that appear in a selectable list. You can also give the list a more meaningful name. Right now, when you click on the grip that opens the list, you see d1 as the name. Try the following to change the name from d1 to Width:

Figure 18.21. The list with the word Width appearing as the column title

As you can see, you have a lot of control over the behavior of various components of the Dynamic Block. In the next section, you'll learn how you can control the visibility of different parts of your block.

Depending on circumstances, you may need a block to display a completely different form. For example, you might want a single generic bath that can morph into a standard bath, a corner bath, or a large spa-style bath with jets.

Using dynamic blocks, you can hide or display elements of a block by selecting a visibility state from a list. For example, you can draw the three different bath sizes and then set up a visibility state for each size. Each visibility state displays only one bath size. You can then select a visibility state depending on the bath size you want.

Try the following exercise to see how this works firsthand:

Figure 18.22. The Bathtub block

If you were to insert this block in a drawing, it would appear just as you currently see it, with each bathtub type overlaid on another. Next, you'll see how you can add control over the visibility of each bathtub type so that only one is displayed at a time.

The first thing you need to do is add a Visibility parameter:

Figure 18.24. The Visibility States dialog

You'll need three visibility states: one for each type of bathtub whose visibility you want to control. You've already got one, but you want a name that is more appropriate to the application:

You have the visibility states you need, and you have the objects whose visibility you want to control. Now you need to determine which block is visible for each state.

Remember that in step 9 of the previous exercise, you made Standard the current visibility state. You'll want only the standard Bathtub block visible for this state. Do the following to turn off the other two Bathtub blocks for the current state:

You've created visibility states and set up the blocks so they appear only when the appropriate visibility state is current. Next, you'll test the blocks:

In this example, you used a set of bathtubs, but you can use the Visibility parameter for anything that requires a different appearance. As mentioned at the beginning of this chapter, another use might be a block that contains a double-, queen-, and king-sized bed. Going back to the door example, you can create a left- and right-hand door in the same block and then use the Visibility parameter to display a left- or right-hand door in the drawing. Figure 18.28 shows such a door block. The Visibility parameter has been renamed Hand in the block. When the door is inserted in the drawing, you see a list that allows you to select Left or Right.

Figure 18.28. The Door dynamic block showing a left- and right-hand door (left), and the Door block as it appears in the drawing (right)

You've seen how actions and parameters can control the behavior of a single object in a block. You can also apply actions to multiple objects so they move or change in unison. The following example shows how you can apply more than one Rotate action to a single Rotation parameter to control two objects:

You can see how this drawing has been prepared for this exercise. The black parts of the drawing, which I'll call gates, are blocks that are constrained to the red lines with coincident constraints. The endpoints of the lines are constrained to the center of the arcs. The horizontal red lines are constrained to the vertical ones, also with coincident constraints, and the vertical lines are constrained at both ends with a Fix constraint (Figure 18.29).

Figure 18.29. How the parts of the block are constrained

You'll use the red lines to define the rotation angle of the parts. The vertical line is fixed in place while the rest of the parts are constrained in such a way to allow a rotational motion.

Now add some angular constraints to define the rotation.

You have the first angular dimensional constraint in place. Next, add a second one to the gate on the right, but this time, you'll use the name of the first angular constraint as the dimension for the second one:

Now you're ready to save the block and try it out:

Figure 18.32. The two parts rotate in unison.

You've got the basic function of the gate working, but you don't want the red lines to appear in the drawing since they are really there to facilitate the action of the gate and not really part of the drawing. Do the following to hide the red lines:

Now suppose you want to have the gates rotate in opposite directions instead of in the same direction. You can add a user-defined formula to modify the behavior of the angular constraints.

Figure 18.33. The gates moving in opposite directions

You can go on to add a block table using the Block Table tool to create a predefined set of angles, just as you did for the Door block earlier in this chapter. You can also add incremental values by using the Properties palette to change the angle constraint in a way similar to how you changed constraints in the sink exercise in the first part of this chapter.

Next, take a look at a way to automatically array objects with dynamic blocks.

Perhaps one of the more tedious tasks you'll face is drawing the vertical bars of a hand railing for an elevation view. You can draw a single bar and then use the Array command to repeat the bar as many times as needed, but when you have to edit the railing, you may find that you're spending more time adding and erasing bars.

In the next example, you'll see how you can create a block that automatically fills in vertical bars as the width of the railing changes. You'll start with an existing drawing of a single vertical bar and an outline of the railing opening around the bar:

Figure 18.35. The Railvertical block adds vertical bars as its width expands.

You can now use this block wherever you need to draw a simple railing with vertical bars. Another example of how the Array action might be used is in a side view of a bolt. You could show the threads of the bolt and use the Array action to increase the number of threads as the bolt is lengthened.

Using Parameter Sets

You probably noticed the Parameter Sets tab in the Block Authoring palette. The options in this tab are predefined combinations of parameters and actions that are commonly used together. For example, the Polar Array set inserts a Polar parameter with an Array action. You only need to supply the object. The Polar Array set causes the associated object to rotate about a center point with a grip. You can also array the object by stretching the grip away from the rotation center.

To associate an object with a parameter set, right-click the action icon included in the set, and then select Action Selection Set

In Chapter 13, you learned how you can attach data to blocks through attributes and then extract that data to spreadsheets or AutoCAD tables. You can also include dynamic block information that has been included in a property lookup table. This can be extremely useful for generating data for a bill of materials or in other situations if you need to track the numbers and types of items in your drawing.

To see how this works, you'll return to a version of the Door block that has some additions. This enhanced version of the Door block includes a left- and right-hand version of the door that is controlled with the Visibility parameter. Figure 18.36 shows the door inserted into a drawing using different door sizes and left and right variations.

Figure 18.36. The door block inserted several times into a drawing with various widths and handedness

You'll use the Attribute Extraction command to see how the dynamic block data appears as an exported table or a spreadsheet:

This is the end of the door example, so you can exit this file. Save it for future reference if you like.

Figure 18.38. The resulting table to be extracted, as shown on the Refine Data screen of the Attribute Extraction Wizard

As you can see in Figure 18.38, a list is generated that shows each door in the drawing with its size and handedness. You could use this data as part of a door schedule.