The 10 best and most popular places for 3D model downloads: we compared 3D model databases and for price, quality, selection, and printability. STL is the standard file type used by most additive manufacturing (or 3D printing) systems. We've compiled tips on exporting for the best “surface: file” size ratio below. Download and install the plugin; Select Tools > Export to DXF or STL and to preserve areas where high poly count is critical for your model, click here.