Design & Tech CAD
Fundamentals
Sub Assemblies
Patterns
Explode states & X sections
Bottom Up or Top Down Design
Building associativity through assemblies
Modelling in assembly mode
Model Analysis
Sub Assemblies
Sometimes it is easier [or more logical] to manage a product by organising some parts into separate assemblies and then assembling those into the top assembly. These are referred to as subassemblies.
In the above example the petrol drill is split into many logical subassemblies and sub subassemblies!
Choosing appropriate, robust references when bringing in a subassembly is important. Think about it logically, it is likely that you will use references in the base part in the subassembly to connect to the relative part in the top assembly.
Assembly references must be considered very differently when using a top down design approach - see the Bottom Up or Top Down section.