Bl
Bl
Bl
Bl
Bl
You are here:   Home »  Products »  PolyTrans|CAD+DCC  
Bl

Home > Supported File Formats > IFC to Universal Scene Description


How to convert IFC (Industry Foundation Classes) to Universal Scene Description (.usd,.usda, .usdc.usdz)?


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.

     

IFC

The Industry Foundation Classes (IFC) is a CAD data exchange object-based file format with a data model developed by buildingSMART to facilitate interoperability in the architecture, engineering and construction (AEC) industry, and is a commonly used collaboration format in Building information modeling (BIM) based projects.

IFC files can be written out by such industry standard programs as: ArchiCAD, Allplan, Autodesk's AutoCAD and Revit, Microstation, Tekla Structures, SmartPlant3D and Vectorworks.

Please note: you would always want to use the DWF-3D file format and the Okino DWF-3D file importer to import 3D model data from Autodesk's AutoCAD, Navisworks and Revit, as well as AVEVA's PDMS software.

It is may be safe to say that few 3D graphics users properly understand IFC or why/how it should be used, when it should be used or how it is to be used. In simplistic terms, IFC is NOT a universal data interchange file format like COLLADA, FBX, 3ds, OBJ, DXF, DWG, etc. Rather, IFC is more of an "abstraction" for an architectural model so that BIM companies can exchange IFC files for design iterations without any loss in overall geometric quality. Hence, the basis of IFC is to make an abstract building with stories, floors, doors, columns, windows, etc. From these hang "abstractions" such as 2D plan views and 3D renderable geometric data.

While IFC can be considered a standardized file format by BuildingSmart, not all 3D programs or 3D viewers will "interpret" an IFC file in the same manner due to the abstract nature of the file format and also by the generally loose manner in which a model can be defined and with different contexts and representations.

     

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