Click, Snap! Using Named Mate References with Sub-Assemblies
If you're like me, you want to save time. You want to be more productive. And SolidWorks has many tools to aid you. For example, creating the needed geometrical relations between components in an assembly (called "mates") is sped up with SolidWorks' "Smart Mates" technology. Hold down the ALT-key, click and drag a face or an edge over to other geometry. Viola! A new mate (or two) is quickly created.
In the same vein, mates can be pre-described on components such that they more quickly snap in to place when inserted in to an assembly. These are called "Mate References." AND, if the Mate References in the part has the same name as a Mate Reference in the assembly then you can save even more time! However, the terminology in SolidWorks' Help file refers specifically to the use of Mate References with regards to individual parts (components) only. Does this mean you can't do the same with sub-assemblies?
Thankfully the answer is a resounding No! With a little extra reference geometry, one can easily leverage Mate References for sub-assemblies to allow them, also, to SNAP in to place in a top-level assembly. I'll show you how:

I begin with creating common reference geometry in both the sub-assembly and the top-level assembly. In the images to the right, you see just that. (you do not have to name the reference geometry identically but it helps from a documentation standpoint)
You then create an identically named Mate Reference in both the sub-assembly and top-level assembly.
Select the appropriate reference geometry items to populate the Mate Reference in addition to their appropriate mate conditions and alignment. (see the thumbnailed image to the right)
The thumbnailed images below show the two identical Mate References I added to both models. When the sub-assembly is inserted in to the top-level assembly, you need only click once to finish placing it. See the image below.
And the final assembly tree, complete with mates, you can review by clicking the last thumbnailed image to the right. You can see, hopefully, that with the right references in place, using named Mate References will allow you to quickly insert your sub-assemblies in to upper-level assemblies.
