Structures can vary greatly from company to company and your needs for a structure will depend on your application. A great advantage for golf simulators is the ability to add the systems to an existing projection-based system, because of this many times a true structure is not necessary or can be customized to suit your needs.
The industry trend for golf simulator structures is getting smaller and smaller. The average structure size is around 10'X10'X10'. Most of the structures on the market today are large and are designed to be placed in a semi-permanent location. You can also look for home indoor golf simulator via https://thenetreturn.com.au/collections/skytrak-golf.
If you are looking to add a golf simulator to a commercial application here are a few things to consider.
The cost of a replacement screen can run you anywhere between $300 and $1500. All high-impact screens I've come across will get what is called "friction burns". These are made by the golf balls hitting the screen at high velocity. While the screen and system will work just fine with a lot of friction burns, the screen will look warn. Most screens will last around three years in a commercial setting. Using clean, undamaged golf balls will help to maximize the life of your screen.
What warranties are available for structures?
Manufacturers will offer between 1 and 3-year warranty on the structures but some don't so make sure to ask. This is also a major pitfall in buying a used simulator without a warranty it can be a risk.
Which structure you choose will most likely come down you how much space you have and how much money you are willing to spend.