Hi, I need to construct two bodies that can be fitted to one another.  I have one of the bodies completed, and it contains a complex surface geometry.  I need to construct a second body that has a similar surface geometry (offset by .25") to the first.  The two bodies then need to be fitted and bolted to one another.

The creation of the second body needs to be built with geometry references to the first (the complex surface geometry, the bolt holes, alignment pins, etc.).  What is the proper way to construct the second body?  Do I create a new part file (for the second body) and then insert the first for reference?  Or, am I supposed to build the second part in the assembly environment?

Thanks