A block can be composed of objects drawn on several layers with various properties. You can use several methods to create blocks.
How Blocks Are Stored and Referenced
Every drawing file has a block definition table that stores all block definitions, which consist of all information associated with the block. It is these block definitions that are referenced when you insert blocks in your drawing.
Each rectangle below represents a separate drawing file and is divided into two parts:
When you insert a block you are inserting a block reference. The information is not copied from the block definition to the drawing area. Instead, a link is established between the block reference and the block definition. Therefore, if the block definition is changed, all references are updated automatically.
Use PURGE to remove unused block definitions from a drawing.
A block can be composed of objects drawn on several layers with various colors, linetypes, and lineweight properties. Although a block is always inserted on the current layer, the block reference preserves information about the original layer, color, and linetype properties of the objects that are contained in the block. You can control whether objects in a block retain their original properties or inherit their properties from the current layer, color, linetype, or lineweight settings.
You can also create annotative blocks. For more information about creating and working with an annotative blocks, see Create Annotative Blocks and Attributes.
