Block definitions can also include attribute information. Although the block was broken into its entities, the block definition remains in the drawing. Redefining a Block Redefining a block is a great way to update information. To redefine an block definition you can either create a new block with the same name or insert a revised block with the same name. You will be prompted that the block definition existing in the current drawing and whether or not you wish to redefine the block, yes or no.
Redefinition affects all occurrences of the block with the same name.
Layers and Blocks Layer information is critical when you create new block definitions. Layer names are inserted as part of the block definition. This also helps with block layer visibility. If you find that your layers are mysteriously being frozen, you may have a number of layers defined in your block. The list sub-command will list all the block names that are in the current drawing.