There are certain situations where this would be very helpful. I know Catia has the ability to create multiple solid bodies inside the same part. This is really nice when you have something that really is an assembly, but you don't want to manage it as such. It's much easier to purchase, track, and duplicate a single part (both in a PDM system and outside of it), and this can make sense if it's really treated that way in real life. If it will be a single line on the BOM, and have one drawing, and is not intended to be disassembled and altered, the single model makes much more sense. Some examples:
- Demountable Pins and Bushings with toe clamps (and possibly fasteners)
- Purchased components that move - hydraulic cylinders, gas springs, etc.
- Purchased assemblies (Standard Lifters, conveyors, valves, manifolds, fittings, etc.
Unfortunately, from what I understand this is fundamentally not possible with the Creo's (Granite) kernel. Creo treats all solid geometry in each part as one set of solid geometry. It will warn you if there are separated pieces of solid geometry contained in the same part. If you do create separate pieces of geometry, as soon as they touch they instantly "merge".
I have two basic "solutions".
- Create an assembly. Of course you will end up with dozens to hundreds of individual parts for each assembly that now need to be tracked in the PDM system, excluded from BOM's, etc.
- Create a single part. To make this work you need to make sure that there is a small gap between separate pieces of solid geometry (ignore the warnings), and physically change the sizes of things to simulate movement. You also may need to keep the model accuracy high enough to prevent things from automatically re-combining.
We actually have automation built that will take assemblies (typically downloaded from the Internet) and merge each individual component into one new, single part. That part is then exported and re-imported creating a single file to represent that assembly.