AutoCAD 2008 User's
Guide > Create and Modify
Objects > Create and Use
Blocks (Symbols) > Modify
Blocks >
Modify a Block Definition
When you redefine block definitions in your current drawing, both previous and future insertions of the block in the drawing are affected.
You can redefine block definitions in your current drawing. Redefining a block definition affects both previous and future insertions of the block in the current drawing and any associated attributes.
There are two methods for redefining a block definition:
The method you choose depends on whether you want to make changes in the current drawing only or in a source drawing also.
Modify a Block Definition in the Current Drawing
To modify a block definition, follow the procedure to create a new block definition, but enter the name of the existing block definition. This replaces the existing block definition, and all the references to that block in the drawing are immediately updated to reflect the new definition.
To save time, you can insert and explode an instance of the original block and then use the resulting objects in creating the new block definition.
Update a Block Definition That Originated from a Drawing File
Block definitions created in your current drawing by inserting a drawing file are not updated automatically when the original drawing is modified. You can use INSERT to update a block definition from the drawing file.
Update a Block Definition That Originated from a Library Drawing (Advanced)
DesignCenterâ„¢ does not overwrite an existing block definition in a drawing with one that comes from another drawing. To update a block definition that came from a library drawing, use WBLOCK to create a separate drawing file from the library drawing block. Then, use INSERT to overwrite the block definition in the drawing that uses the block.
Modify the Description of a Block
To modify the DesignCenter description of a block definition, use BLOCK. You can also add descriptions to any number of existing blocks in the Block Definition dialog box.
You can attach attributes to a block when you define or redefine that block. When you are prompted to select the objects to include in the block definition, include the desired attributes in the selection set. Redefining the attributes in the block definition has the following effects on block references that were previously inserted:
