JT is a 3D data format developed by Siemens PLM Software (formerly UGS Corp.) and is used for product visualization, collaboration, and CAD data exchange. It can contain any combination of approximate (faceted) data, boundary representation surfaces (NURBS), Product and Manufacturing Information (PMI), and Metadata (textual attributes) either exported from the native CAD system or inserted by a product data management (PDM) system.
JT is the common language of PLM and is the world’s most widely used 3D format. JT is the first ISO International Standard ( IS 14306-1) for 3D visualization and collaboration. Compact and accurate, JT is used throughout the product development lifecycle in all major industries to communicate the critical design information typically locked up inside a CAD file.
Overview
JT files are used in product lifecycle management (PLM) software programs and their respective CAD solutions, by engineers and other professionals that need to analyze the geometry of complex products. The format and associated software is structured so that extremely large numbers of components can be quickly loaded, shaded and manipulated in real-time. Because all major 3D CAD formats are supported, a JT assembly can contain a mixture of any combination which has led to the term “multi-CAD”. As JT is typically implemented as an integral part of a PLM solution, the resulting multi-CAD assembly is managed such that changes to the original CAD product definition files can be automatically synchronized with their associated JT files resulting in a multi-CAD assembly that is always up-to-date.
Because JT files are inherently “lightweight” (~1-10% of the size of a CAD file) they are ideal for internet collaboration. With the growing trend toward globalization, more companies are leveraging resources wherever they are available in the world. Collaboration using JT allows companies to send 3D visualization data to suppliers and partners much more easily than sending the associated “heavy” CAD files. In addition, real-time, on-line collaboration is easier because the amount of information sent back-and-forth across the internet is reduced. Finally, JT provides an inherent security feature such that intellectual property does not have to be shared with inappropriate parties. As indicated above, JT can contain any combination of data such that the right amount of information can be shared without exposing the underlying proprietary design definition information.
History
JT was originally developed by Engineering Animation, Inc. and Hewlett Packard as the DirectModel toolkit (initially Jupiter). JT is the abbreviation for Jupiter Tesselation. When EAI was purchased by UGS, JT became a part of UGS Corp.’s suite of products. Early in 2007 UGS announced the publication of the JT data format easing the adoption of JT as a master 3D format. Also in 2007, UGS was acquired by Siemens AG and became Siemens PLM Software. JT is the common interoperability format in use across all of Siemens PLM Software and has been adopted as the long term data archival format across all of Siemens.
Data Model
The JT data model is capable of representing a wide range of engineering data. This data can be very lightweight, holding little more than facet data or it can be quite rich, containing complete NURBS geometry representations along with product structure, attributes, meta data and PMI. It also supports multiple tessellations and level-of-detail (LOD) generation.
- Product Structure – assembly, part, instance
- Facet – polygon, polygon set
- Lighting – light set, point light, infinite light
- Textures
- Precise Geometry and Topology – point, curve, surface, face, loop, edge, vertex
- Boundary representation (B-rep) could used either JT B-rep and T B-rep(Parasolid) format, STEP B-rep will be supported by ISO JT edition 2 (ISO 14306-2) that will be published by 2017
- Geometry Primitives – box, cylinder, pyramid, sphere
- Product Manufacturing Information (PMI) – GD&T, 3D annotations
- Attributes / Properties – text, integer, float, date, layers
by the materials of Wikipedia.org
