It is possible to use a 3D printer to make giant alphabet letters for a classroom. The first step is to make a virtual design of the letters in computer aided design file using a 3D modeling program.
Yeggi.com provides free alphabet files that can be printed by a 3D printer. The printers create objects layer by layer. Each layer is blended together so that no indication of the layering process is visible. Three common methods of 3D printing are selective laser sintering, fused deposition modeling, and stereolithography. As of 2015, printer prices range from under $100 to over $800,000.