Understanding the Annotation Scale

Understanding the Annotation Scale
One common use for AutoCAD’s block feature is creating reference symbols. These are symbols that
refer the viewer to other drawings or views in a set of drawings. An example would be a buildingsection
symbol on a floor plan that directs the viewer to look at a location on another sheet to see
a cross-section view of a building. Such a symbol is typically a circle with two numbers: one for the
drawing sheet number and the other for the view number on the sheet (examples appear a little
later, in Figure 4.8).
In the past, AutoCAD users had to insert a reference symbol block multiple times to accommodate
different scales of the same view. For example, the same floor plan might be used for a 1⁄4˝ =
1´1˝ scale view and a 1⁄8˝ = 1´0˝ view. An elevation symbol block that works for the 1⁄4˝ = 1´1˝ scale
view would be too small for the 1⁄8˝ = 1´0˝ view, so two copies of the same block were inserted, one
for each scale. The user then had to place the two blocks on different layers to control their visibility.
In addition, if sheet numbers changed, the user had to make sure every copy of the elevation symbol
block was updated to reflect the change.
The annotation scale feature does away with this need for redundancy. You can now use a single
instance of a block even if it must be displayed in different scale views. To do this, you must take
some additional steps when creating and inserting the block. Here’s how you do it:
1. Draw your symbol at the size it should appear when plotted. For example, if the symbol is
supposed to be a 1⁄4˝ circle on a printed sheet, draw the symbol as a 1⁄4˝ circle.
2. Open the Block Definition dialog box by choosing the Make Block tool from the 2D Draw
control panel.
3. Turn on the Annotative option in the Behavior section of the Block Definition dialog box.
You can also turn on the Match Block Orientation To Layout option if you want the symbol
to always appear in a vertical orientation.



4. Select the objects that make up the block, and indicate an insertion point as usual.
5. Click OK.
After you’ve followed these steps, you need to apply an annotation scale to the newly created block:
1. Click the new block to select it.
2. Right-click, and choose Annotative Object Scale  Add/Delete Scales. The Annotation
Object Scale dialog box appears.


3. Click the Add button. The Add Scales To Object dialog box appears.


4. Select from the list the scale you’ll be using with this block. You can Ctrl+click to select multiple
scales. When you’re finished selecting scales, click OK. The selected scales appear in the
Annotation Object Scale dialog box.
5. Click OK to close the Annotation Object Scale dialog box.
At this point, the block is ready to be used in multiple scale views. You need only to select a scale
from the Model view’s Annotation Scale drop-down list or the Layout view’s VP (Viewport) Scale
drop-down list, which are both in the lower-right corner of the AutoCAD window.



The Annotation Scale drop-down list appears in Model view, and the VP Scale drop-down list
appears in Layout view and when a viewport is selected (see Chapter 16 for more about layouts and
viewports). In Layout view, you can set the VP Scale value for each individual viewport so the same
block can appear at the appropriate size of different scale viewports (see Figure 4.8).
Note that if you want to use several copies of a block that is using multiple annotation scales, you
should insert the block and assign the additional annotation scales and then make copies of the block.
If you insert a new instance of the block, the block acquires only the annotation scale that is current
for the drawing. You’ll have to assign additional annotation scales to each new insertion of the block.
If you’re uncertain whether an annotation scale has been assigned to a block, you can click the
block, and you’ll see the different scale versions of the block as ghosted images. Also, if you hover
over a block, a triangular symbol appears next to the cursor for blocks that have been assigned
annotation scales.





If you need to change the position of a block for a particular layout viewport scale, go to Model
view, select the appropriate scale from the Annotation Scale drop-down list, and then adjust the
position of the block.