AMF stand for Additive Manufacturing File Format. Is a new XML-based open standard for 3D printing. Unlike STL, it contains support for color. They can also be compressed to about half the size of a compressed STL file.
An OBJ file is a very common type of 3D file and it is often used as an alternative to STL file when information about colours or materials are desirable. Moreover, contrariwise to STL file, can process non-triangular faces (quadrilaterals, etc.), along with the challenge that these faces must remain flat. The OBJ file format was developed by Wavefront Technologies (designers of 3D Maya modelling software) for its Advanced Visualizer package.
STL Stands for “stereolithography” – it is a 3D rendering that contains only a single color. STL has become the standard file format for all Additive Manufacturing processes. STL file is a mesh of tessellated triangles applied to the surface of CAD model. CAD geometry is approximated as a set of triangular facets. The accuracy of the approximation is controlled by setting the number / size of triangles. The number of triangles (accuracy of geometry) also governs data processing speed.
WRL stands for “Virtual Reality Modeling Language” – it is a newer digital 3D file type that also includes color, so it can be used on desktop 3D printers with more than one extruder (2 or more nozzles that each can print with a different color plastic), or with full-color binder jetting technology.