Inventory management allows you to compare your current layout with up to two other files. By reusing parts that are in an existing layout for the same space, or even parts that are in storage, you can reduce the number of new parts that you must order for a new layout. This feature works with CDB (design) files only. In the following example, Existing. CDB is the original office layout sold last year. The same company has decided to expand and New. CDB is the new layout.