In assembly modeling, you combine parts and subassemblies to form an assembly that functions as a single unit. Parts and subassemblies are related to one another by assembly constraints. can also define a set of features in the assembly that interact with multiple parts.

When you create or open a file of the assembly type (.iam), you are in the assembly environment. When you create or open a file of the part type (.ipt), you are in the part modeling environment. Part tools and commands manipulate sketches and features, which combine to form parts. You insert parts into assemblies and constrain them in the positions they will occupy when the assembly is manufactured.

You can insert existing parts into an assembly or use sketch and part modeling commands to create parts in the context of an assembly. In an assembly, you group parts that function together as a single unit (subassembly). A subassembly can also be inserted into other assemblies. Combining multiple subassemblies to build an assembly makes design changes easier to manage.

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