I needed a structure to represent a "iron and steel fabrication shop" for a corner scene on my layout. Basically, I wanted a place for a couple of flat cars or a couple of gondolas to be spotted bringing in steel in sheets or I beams, etc and finished products being shipped to oil field job sites in small towns. I wanted something that I could perhaps spot a car inside and another outside under an overhead crane.
I contacted Joe at OGR Forum Sponsor Model Structures and gave him my basic design. This is the structure he built for me:
The part of the structure on the left is simply a 1/4 inch thick "flat" that represents the portion of the building where most of the "fabrication" takes place. The "3-D" loading shed is where some of the loading takes place.
The above photo was taken in Joe's shop prior to shipping to me. He has this photo along with another large structure he built for me on his website.
The "kitbashed OGR AmeriTowne structures and flats" structure is also a view block similar to the concept AGHRMatt used (tall structure to be used as a view block) but with the added benefit of being painted differently with different components (few windows and 4 loading docks as opposed to lots of windows and three loading docks). Since you can only see one side at a time, the "one structure-two industries" concept works...at least for me...and it IS my railroad, right?
Back to the original iron and steel fabrication shop...I have since added an overhead crane structure so the pipes, I-beams and sheet (or rolled) steel can be off loaded from the gons and flats.
Granted, everything is in disarray right now as I am rebuilding some of those areas, but I have the structures ready to go back with the revised track plan.
Since my layout is a shelf (approximately 24-30 inches, around the walls of a 16ft x 20ft building in my back yard with a 4ft x 10ft center peninsula where the AmeriTowne structure lives as a view block) most of my structures are flats. Thus my grain elevator with the "loading shed" and the iron and steel fabrication shop give special visual treatment to those structures, just as the different wall sections and paint and door arrangements on the AmeriTowne building give each of those structures unique appearance on my layout.
I have been fortunate that I was able to acquire some very nice custom structures via friends and commercial services along with eBay and some of our fellow OGR Forum members. I have some completely scratch built (such as the large grain elevator and flour mill made with sheet styrene and 4 inch diameter PVC pipe; building flats made from OGR AmeriTowne building fronts or backs; mat board structures; wall panels from Korber kits...and more,
I simply do not have the room in my "storage building" layout space to have very many "3-D" structures, so the custom built iron and steel fabrication shop was a compromise for me to have a low relief structure but still have room for an internal loading dock.
I hope something in those comments is useful and perhaps helps you pick some options that might work well for your needs.
Now, I should also admit that I have very few structures that I built. The last time I tried to work with any "super glue" product, I spent 12 hours in the ER waiting my turn to have my fingers cut apart...and I am still waiting on the hair to grow back on my head where I scratched....(just kidding)
(or was I?)