Creating a Part in an Assembly
You can create a new part in the context of an assembly. That way you can use the geometry of other assembly components while designing the part.
You can also create a new subassembly in the context of another assembly. See Inserting a New Subassembly.
Before you begin:
Specify the default behavior for saving new in-context components. You can save them as separate external part files or as virtual components within the assembly file. See Saving New In-Context Components.
To create a part within an assembly: