A 3D (three-dimensional) file is an electronic file representing a three-dimensional object. It is created via 3D modelling, which is the process of developing a mathematical representation of any 3D surface of an object via Computer Aided Design (CAD) software. It is also called a 3D model. A 3D file or model can generally be printed with a 3D printer.
Common 3D file formats are .STL, .OBJ (Wavefront), .SKP (Sketchup), .3DS (3D Studio), .DXF (AutoCAD) and .SCAD (OpenSCAD).