According to Merriam-Webster.com, 3D printing is "the manufacturing of solid objects by the deposition of layers of materials (such as plastic) in accordance with specifications that are stored and displayed in electronic form as digital model."
It might be easier to ask what can't be done with 3D modeling. 3D models can have medical, engineering, art, architecture, gaming, manufacturing and marketing applications, the sky is the limit. Actually the sky is not the limit. 3D printing in space offers NASA a quick and inexpensive way to manufacture parts on-site and on-demand. For more information on how 3D printing is being used, please see the Special Topics page.
There is no single answer for how long it takes to complete a 3D model. Factors include: the software used, the design and complexity of the model, the size of the model, the printer equipment used to create the model. Some objects could be created in an hour, while others take many hours or even days.
"Resin 3D printing, however, is dramatically different and has unique demands that should make you think twice before investing. The resin is, to varying degrees, smelly. Sometimes noxious. And highly toxic for the environment and harmful with prolonged contact on the skin. It requires dedicated cleanup stations and personal protective equipment. You typically will need 95%+ isopropanol to clean prints, dissolving uncured resin from the surfaces.
All printers should be operated in well-ventilated spaces, but this applies doubly so for resin 3D printers." -- https://all3dp.com/1/3d-printers-on-sale-deals/