You can build assembly models the same way you design them - from the "bottom up" or from the "top down." In either case, the assembly is made up of components that are either created or inserted (instanced) into the assembly.

When components are added to an assembly, parent/child relationships are formed. These relationships are graphically displayed in an assembly tree. Components are parametrically related by alignment constraints. These constraints contain information about how a component should be positioned within the assembly hierarchy and how it should react if other components are modified.

Working within the context of an assembly is made easier by allowing you to apply more commands to other components and sub-assemblies (that are not active). These include the Inquire, Point, Annotation Text, Datum Plane and Pattern Component commands. Large assembly performance is enhanced by eliminating unnecessary redraws and enhanced display management while zooming.