Every object in a OpenBridge Modeler model - each concrete object, cage, and piece of rebar - is a "part." Each part is identified in the system with a unique part number. Parts are used in the detailing process when you create 2D drawings and material lists.

Individual parts can be members of:

• Groups - A collection of parts built around a main part. Example: A beam, stiffeners, and plates, in which the beam is the main part.
• Sub-groups - A collection of parts contained within a larger collection of parts.
• Assemblies - A collection of parts that does not have a main part.

Use the topics that follow as a guide to working with parts and part families.