I see what you're saying and I suppose that is a viable method but given the complexity of the assembly individually thickening each face would be really time consuming, but scaling could be the right idea.
I guess to try and re-iterate the problem we have a large machine made up primarily of sheet metal and welded structural metal (tube/angle, etc...) which we're trying to create a 3d file of to use at a trade show. Currently we're looking to scale the file to 1:15 size and our supplier recommends a minimum wall thickness of any part of the printed file to be at least .031". Given that we're exporting at 1:15 that means that anything modeled under .465" thick will need to be thickened. The assembly is roughly 1,000 components and most of the assembly is sheet metal which is bolted to structural. There'd be roughly 100~200 thicken operations to ensure that everything is thickened to the point where it's a solid object, or hundreds more to make it a hollow object but with the minimum wall thickness.
Most of my understanding of what is possible comes from over a decade in SolidWorks and praying that Inventor has the same capability, so in this case I'd like to export the file as a single solid body, scale it, then create the STL file. This should be the easiest method but Inventor seems to be pushing back.
I think this should add a bit of clarification to what I'm trying to do