An assembly is a list of parts.

It is denoted with a folder icon in the Model Browser. Assemblies can contain subassemblies, allowing you to organize your model hierarchically.

You can create and edit assemblies using the right-click context menu in the Model Browser. Parts and subassemblies within an assembly are positioned in space relative to the parent assembly. If you translate or rotate a parent assembly in the modeling window, its parts and subassemblies move with it.

Assemblies do not have their own properties. Changing properties for an assembly in the Property Editor actually applies the change to the individual parts within the assembly down to the lowest level in the hierarchy. Only properties common to all parts in the assembly are shown.