2004

340 | Chapter 16 Draw Geometric Objects
Attribute information extracted from a drawing can be used in a spreadsheet
or database to produce a parts list or a bill of materials. You can associate
more than one attribute with a block, provided that each attribute has a
different tag.
Whenever you insert a block that has a variable attribute, AutoCAD prompts
you to enter data to be stored with the block. If the block has only constant
attributes, attributes whose values do not change, AutoCAD does not prompt
you for a value when you insert the block.
Attributes also can be "invisible." An invisible attribute is not displayed or
plotted; however, the attribute information is stored in the drawing file and
can be written to an extraction file for use in a database program.
Define Block Attributes
To create an attribute, you first create an attribute definition, which describes
the characteristics of the attribute. The characteristics include the tag (which
is a name that identifies the attribute), the prompt displayed when you insert
the block, value information, text formatting, location, and any optional
modes (Invisible, Constant, Verify, and Preset).
After creating the attribute definition, you select it as one of the objects when
you define the block. Then, whenever you insert the block, AutoCAD
prompts you with the text you specified for the attribute. For each new block
insertion, you can specify a different value for the attribute.
To use several attributes together, define them and then include them in the
same block. For example, you can define attributes tagged "Parts," "Materi-
als," and "Thickness," and then include them in a block called
PARTS_DATA.
attribute definition blocks with attributes