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Home > Supported File Formats > Universal Scene Description to Unity


How to convert Universal Scene Description (.usd,.usda, .usdc.usdz) to Unity?


PolyTrans|CAD+DCC performs mathematically precise CAD, DCC/Animation, GIS and BIM 3D file conversions into all key downstream 3D packages and file formats. Okino software is used and trusted throughout the world by many tens of thousands of 3D professionals in mission & production critical environments, backed by respectable personal support directly from our core development team.

     

Universal Scene Description

The USD format (“Universal Scene Description”) is an open 3D model and scene format designed for efficient storage and streaming of 3D asset data. It is a high-performance extensible framework and ecosystem for describing, composing, simulating, and collaboratively navigating and constructing 3D scenes. An extensive overview of USD is provided in the Okino USD documentation.

Pixar Animation Studios originally created the USD platform (as its fourth generation variation after its Marionette & Preso systems) to improve studio-wide collaborative workflows. USD provides a concept of "scene composition", building a unified scene from potentially thousands of loosely-coupled source assets. For example, the mesh, rigging, materials, and animation for a single model might all come from different "layers" (files), each created and maintained by a different artist or department. Layers can store multiple "variants" of any given data, helping to solve problems of versioning/approval. The coupling between layers is very dynamic and loose, allowing for greater flexibility during the production process. The entire USD system is designed to facilitate a large studio making feature films, with all of the scale that that implies.

USD should be considered more of a code framework (“OpenUSD”) for use in group collaboration, to help with the aggregation of various 3D data sources into a unified scene through a process referred to as scene composition. A subset of that code framework provides for reading and writing USD disk-based files as well as rendering USD scenes (Hydra). The system is rather complex to implement (for software developers) and to use (from first principles) as a 3D graphics artist. The USD file format itself is not for faint of heart and is best read/written using the OpenUSD SDK + various programming APIs. More commonly used ASCII 3D file formats such as COLLADA, VRML2 and Wavefront OBJ are much easier to manipulate/understand/use on a human level basis.

File extensions used by the standard include:

  • .usd, Either ASCII or binary-encoded
  • .usda, ASCII encoded
  • .usdc, Binary encoded
  • .usdz, Zero-compression, unencrypted zip file

     

Unity

Unity is a cross-platform game engine developed by Unity Technologies, first announced and released in June 2005. The engine has since been gradually extended to support a variety of desktop, mobile, console and virtual reality platforms. It is particularly popular for iOS and Android mobile game development.

Okino has long supported Unity as the first and main 3D conversion program to do so. In the simplest terms possible, conversion from Okino software to Unity is done via the FBX file format.

For those who may be unaware of Okino software, for over 30+ years we have been the pioneer 3D conversion company that wrote the rule book on how DCC, animation and MCAD data is to be cross-converted between all major 3D programs and file formats. Key uses of our software for Unity users has been for the conversion of all major MCAD data formats into a highly optimized and efficient form for realtime usage within Unity. We also invented the processes for animation + skinning/bones cross conversion so that is well supported for Unity. As a minor point of interest, Okino was also the very first implementor of the FBX file format as of 2002, long before Autodesk bought the bankruptcy assets of Alias Research and provided free access to the FBX SDK; hence, we provide highly reliable and robust FBX v5/v6/v7 support.