Home > Supported File Formats > ACIS SAT to Universal Scene Description

How to convert ACIS SAT (.sat,.sab) 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.

ACIS SAT

ACIS 'SAT' (ASCII) and 'SAB' (binary) are the native 3D file formats of the Spatial ACIS solids modelling toolkit. Spatial licenses this toolkit to third party developers upon which they can develop their own 3D software and/or converters.

From Okino's own perspective, the ACIS SAT file format was more prevalent and popular in the late 1990s and into the early 2000s. However, thereafter, several major software vendors moved off of the ACIS platform and onto other alternative platforms to build their software. We really do not have any of our customers utilize the SAT file format anymore as there are better or more native methods to source such MCAD data (such as STEP, IGES and Parasolid).

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

ACIS SAT import converter's overview

Universal Scene Description export converter's overview