Cadtales

Creating and using annotative blocks
Part One

AutoCAD 2008 introduces a new object property called ?annotative,? which can be applied to Blocks, Attributes, Text, Dimensions, Hatches, Tolerances and Multileaders. This property allows you to automate the process of scaling annotations and other features so that they plot or display at the correct size on paper. Instead of creating multiple annotations at different sizes and on separate layers, you can turn on the annotative property by object or by style, and set the annotation scale for layout or model viewports. The annotation scale controls the size of the annotative objects relative to the model geometry in the drawing. To introduce you to the annotative property, Part 1 of this article will illustrate how to turn on the annotative property for an object (an annotation block), typically used to identify equipment, a process, or a reference to other sheets or documents. Our sample block will be a simple six-sided polygon with normal block properties. (In the next issue, in Part Two, we?ll show you how to design and use blocks with annotative properties by taking this simple block and adding (3) attributes for ?block name,? ?designation? and ?number?).

As we start several important points are in order.

1. Any ordinary block (object) can have annotative properties turned on and scale settings assigned. This affects only the edited instance of the block and not the block definition, however.

2. For a block to exhibit annotative properties it must be created with annotative properties.

3. For an Attribute to exhibit annotative properties it must be created with Text with annotative properties.

4. Do not scale annotative blocks manually.

CREATING A BLOCK OBJECT
In model space start the Polygon command and create a six-sided polygon using the ?Edge? option to set the edge dimension to 0.25?. Rotate the polygon so that an edge is horizontal and draw a horizontal line from the left node to the right node ? dividing the symbol into upper and lower halves. We?ll use this symbol to represent a machine tag. (In Part 2 we?ll add annotative attributes for ?block name,? ?designation? and ?number?).

In paper space create a new viewport 0.75? x 0.75?, center the symbol in the viewport and set the scale to 1:1. Now copy the viewport to make three additional instances to the right and scale of the new viewports to 1/16?, 1/8? and ?? respectively. Highlight all four viewports, right-click and select Display Locked>Yes. Your drawing should look like Figure 1 below.


Figure 1

Make the 1:1 viewport active. Start the Block (B) command and name the block ?M_TAG.? Pick a Base point (the center of the middle line) and Select objects (all the line objects for the symbol). Check the Convert to block option and finally, check the Open in block editor box at the bottom of the dialog box. Clock OK.

ADDING ANNOTATIVE PROPERTIES TO A BLOCK
To enable annotative properties in an ordinary block open the block in the Block Editor (BEDIT) and, with no objects highlighted, open the Properties Palette (?No selection? in the properties window). Find the Block section and set the Annotative property to ?Yes.? See Figure 2 below. Close the Block Editor and Save the changes.


Figure 2

Click the block to highlight ? then Right-click and pick Annotative Object Scale<Add/Delete Scales? See Figure 3 below. In the Annotation Object Scale dialog box you can add or delete the scales you want to assign to this object. For this example assign the 1/16?, 1/8? and ?? scales. See Figure 4 below. (Remember, we are adding annotative properties to this instance of this block only and NOT to the block definition).


Figure 3


Figure 4

Another way to add annotative scales to a block quickly is to use the Add Current Scale feature also shown in Figure 3 above. You can do this in any viewport without knowing the viewport scale by setting the desired view, right-clicking the block and clicking Add Current Scale. Note: Do not scale annotative blocks manually or the annotative property will not work as expected.

Now that we?ve created our block, turned on the annotative property and assigned the desired scales it?s time to look at the features on the Drawing Status Bar that control the behavior of the annotative property.


Figure 5

Starting at the left of Figure 5 above, note the following functions: Lock/Unlock, Viewport Scale, Annotation Scale, Visibility Button and Automatic Scaling Button. These buttons will be on or off when a viewport is active to show the current status.

Make the 1/16? viewport active and you will see that it is locked. When a viewport is locked, the Annotation Scale settings are not available for edit. Unlock the viewport and set the scale to 1/16? and see the block zoom to the same relative size as the view in the 1:1 viewport. Lock the viewport again. Repeat this operation for the 1/8? and 1/4? viewports.

For the final step in this exercise click the Automatic Scale button shown in Figure 6 below. (This button is off by default and when clicked will change from faded to colors). This will allow the program to add additional scales to the block when the scale of the viewport is changed.

In paper space, copy the right-hand viewport and place to the right. On the Drawing Status Bar unlock the viewport (if locked) and set the Viewport Scale to 3/8?. See the block zoom automatically to the new view scale as the 3/8? scale setting is added to the block.


Figure 6

In Part 2 of this article we?ll add the annotative property to the block definition so that all inserted copies of the block (or dynamic block) will exhibit annotative properties.

Do you see a benefit in applying the annotative property to your blocks, dimensions, attributes, text, hatches and leaders to simplify your drawings and improve workflow? Contact your Hagerman sales representative for software upgrades, training and customization.