Bill Of Materials

 Two types:
Engineering Bill Of Materials (E-BOM)
Manufacturing Bill Of Materials (M-BOM)
The E-BOM and M-BOM are presented as assembly trees that represent a hierarchical structure for the assemblies, subassemblies and parts that makes up the product, whether purchased or manufactured users can create and modify these trees easily. 
Engineering Bill Of Materials (E-BOM)
Defines and manages the components and structure of the product being manufactured.
Contains the list of items, parts, components, sub-assemblies and assemblies in the product designed by engineering.
Linked to design 2D/3D modules (CAD files, PDF,etc.).
All end-items, assemblies, purchased components, manufactured components and raw materials are identified in the E-BOM.
Represents only the physical product being “engineered,” not the packaging or manufacturing consumables.
                                  Manufacturing Bill Of Materials (M-BOM)
Contains details of the parts and assemblies required to build a complete and shippable product. (eg: Kits, Structures, Assembly processes… etc..)
Reflects the manufacturing process, represents physical product, packaging and included documentation (CAD files, PDF,… etc..).
Includes information about how the parts relate to each other.