Which type of file is required to export a model for printing on a 3D printer?

The correct choice, STL, is the most common file format used for 3D printing. STL stands for Stereolithography, which was developed by 3D Systems. This format represents the surface geometry of a 3D object with a mesh made up of triangles. The use of STL files is preferred in the 3D printing industry because they provide a simple and efficient way to represent complex 3D shapes without containing any color, texture, or other attributes beyond shape.

When 3D printing, the printer interprets the STL file to create the model layer by layer, making it essential for accurate printed representations of the original design. Additionally, STL files are widely supported by most slicing software, which is used to prepare 3D models for printing.

Other file formats, while useful in different contexts, do not fulfill the specific needs of 3D printing in the same way. For example, OBJ files can be used to represent 3D models and include color and texture information, but they are not as universally adopted in the 3D printing process as STL files. DXF is a file format used primarily for 2D drawings and CAD data, which doesn't adequately convey the necessary 3D information for printing.