An exchange format is a 3D model file format that doesn’t belong to any particular application, but is used primarily to transfer (exchange) a model between applications. All 3D programs have the ability to export and import at least a few exchange file formats. Contrast with a native file format, the format specific to a 3D application.
Exchange formats are also referred to as generic or open source formats.
Common Exchange File Formats
Exchange formats vary in the amount of information they hold and transfer from one application to another. Features that are specific to a 3D application, such as complex material types, physics simulations, and particle systems, are not held by exchange formats.
All exchange formats hold information on the 3D model’s geometry. However, they vary greatly in how much information they carry about textures, mapping, rigging, and animation, and in how closely they adhere to the original model’s topology.
In general, OBJ and FBX are the best choices for exchanging files between applications, but even they have their limitations.
Holds mapping, standard materials
- Pros: The most popular exchange format for 3D models, OBJ can be exported and imported by just about every 3D application. Quad topology is retained.
- Cons: Does not hold rigging or animation information.
Holds mapping, standard materials, rigging, animation
- Pros: The only exchange format that holds rigging and animation information. A newer format, it can hold more complex material information than OBJ. Quad topology is retained.
- Cons: Older versions of the FBX format often exchange model information better than newer versions.
Holds very limited material information
- Pros: Older models (pre-2005) are sometimes available only in this format.
- Cons: All topology is stored as triangles regardless of the original topology. 3DS cannot reference texture file names more than 8 characters in length, so in models exported to 3DS the texture references are always truncated to 8 characters. OBJ files cannot hold rigging or animation information.
Holds geometry only
- Pros: Exports accurately from CAD programs.
- Cons: Contains no texture or material information. Geometry is often heavily triangulated and messy. Random flipped normals are common.
Holds geometry only
- Pros: Can be exported/imported successfully from NURBS-based applications like SolidWorks and Inventor. Often used for 3D printing or prototyping.
- Cons: Contains no texture or material information. Geometry is often heavily triangulated. Does not retain one-sided surfaces such as planes.