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Technical data interoperability represents a major challenge for industrial companies operating in multi-CAD environments. The JT format (Jupiter Tessellation) has established itself as a standardized solution for the exchange and visualization of 3D data, facilitating collaboration between different departments and business partners.
Initially developed by Siemens, JT is now an ISO standardized open format that allows efficient sharing of 3D models while preserving the integrity of essential technical data. Its design focused on lightness and versatility makes it a preferred choice for visualization, digital mockups, and professional collaboration in many industrial sectors.
JT is distinguished by its ability to contain different representations of product data:
- Faceted geometric data (meshes)
- Exact surfaces (NURBS)
- Manufacturing information (PMI)
- Metadata and textual attributes
- Hierarchical product structure
This versatility allows companies to adapt the richness of JT content according to their specific exchange, visualization, or archiving needs, while maintaining an optimal balance between file lightness and data precision.
History and Evolution of JT Format
The JT format has a rich history that demonstrates its constant evolution to meet the growing needs of the industry in terms of CAD interoperability.
Initial development and acquisitions
JT was originally developed by Engineering Animation, Inc. and Hewlett-Packard under the name DirectModel toolkit (initially Jupiter). The abbreviation JT comes from "Jupiter Tessellation". When EAI was acquired by UGS Corp., JT became an integral part of the UGS product suite.
Standardization and openness
In early 2007, UGS announced the publication of the JT data format, facilitating its adoption as a master 3D format. The same year, UGS was acquired by Siemens AG and became Siemens Digital Industries Software. JT has since been the common interoperability format used in all Siemens Digital Industries software and has been adopted as a long-term data archiving format throughout Siemens.
ISO recognition
On September 18, 2009, ISO officially declared that the JT specification had been accepted for publication as an ISO Publicly Available Specification (PAS). In late August 2010, the vote for the New Work Item Proposal (NWI) for JT as an ISO International Standard was launched by ProSTEP iViP.
Harmonization with STEP
ProSTEP iViP aimed on one hand to publish the JT file format specification as an ISO standard and, on the other hand, to harmonize this undertaking with the development of the new STEP AP 242, so that JT and STEP (especially STEP AP 242 XML) could be used together to ensure major benefits in industrial data exchange scenarios.
Version evolution
The JT format continues to evolve with new versions that improve its capabilities and compatibility. The latest documented version is 10.6, released in 2024, which incorporates advanced features to meet modern needs for digital collaboration and manufacturing.
Technical Characteristics of JT Format
The JT format is distinguished by its sophisticated technical structure that makes it a preferred choice for CAD data exchange in multi-system environments.
Geometric engine and data structure
JT uses a scene graph structure to represent assemblies, with nested subassemblies of parts including nodes and CAD-specific attribute data. This approach allows a hierarchical organization of components that facilitates selective loading and efficient display of complex models.
The format supports two main types of geometric representations:
- Faceted representation (triangular mesh) for lightweight visualization
- Exact B-rep (Boundary Representation) for geometric precision
For exact representation, JT can use different modeling kernels:
- JT B-rep (native)
- XT B-rep (Parasolid)
- STEP B-rep (in the ISO JT V2 version)
Supported data types
JT can contain a rich variety of technical data:
- Product structure: assembly, part, instance
- Facets: polygon, polygon set
- Lighting: light set, point light, infinite light
- Precise geometry and topology: point, curve, surface, face, loop, edge, vertex
- Geometric primitives: box, cylinder, pyramid, sphere
- Manufacturing information (PMI): GD&T, 3D annotations
- Attributes/properties: text, integer, float, date, layers
Compression techniques
One of JT's major strengths lies in its advanced compression algorithms that minimize file size without compromising data integrity or visual quality. Faceted information (triangles) is stored using geometric compression techniques that optimize storage efficiency while maintaining acceptable visual accuracy.
This compression allows large and complex models to be transmitted quickly over networks, facilitating remote collaboration and reducing storage requirements. By finding a balance between compactness and fidelity, JT files optimize data transfer efficiency without sacrificing crucial information.
Key Functionalities of JT
The JT format offers several functionalities that make it a powerful solution for CAD data interoperability in modern industrial environments.
Efficient visualization capabilities
JT was designed to allow interactive display of very large assemblies (containing tens of thousands of components). This capability is particularly valuable in industries such as automotive and aerospace, where products have a considerable number of parts.
The JT format uses a level of detail (LOD) approach that optimizes performance:
- Storage of faceted representations with different levels of detail
- Display of a simple and coarse model for the overview
- Progressive loading of finer representations when zooming on an area
- Unloading of non-visible representations to save memory
Product structure representation
JT supports various file structure configurations to efficiently represent complex product hierarchies. This flexibility allows adapting data representation to the specific needs of each use:
- Complete assemblies with their hierarchies
- Relationships between components
- Instances and positioning
- Associated metadata information
PMI support (Product Manufacturing Information)
The JT format allows the inclusion of product manufacturing information (PMI), essential for modern design and production:
- Geometric dimensioning and tolerancing (GD&T)
- 3D annotations
- Manufacturing notes
- Symbols and other technical indications
This PMI support facilitates the adoption of Model-Based Definition (MBD) approaches where all information necessary for manufacturing is directly integrated into the 3D model, reducing the need for traditional 2D drawings.
Level of detail management (LOD)
JT offers sophisticated level of detail management that optimizes performance when visualizing complex models:
- Definition of multiple representations at different resolutions
- Configurable tessellation parameters (chordal and angular precision)
- Visual quality versus file size control
- Adaptive loading based on visualization needs
This functionality is particularly important for large assemblies where visualization performance can be critical for user experience.
CAD Interop Solutions Supporting JT
CAD Interop offers several powerful solutions for working with the JT format, covering the entire 3D data lifecycle, from visualization to archiving through validation and automated exchange.
3DViewStation for visualization and JT conversion
3DViewStation is a powerful solution that allows efficient visualization and analysis of JT format models, even the most voluminous ones. This platform also offers conversion capabilities to and from the JT format, facilitating interoperability with other CAD systems.
The main features include:
- High-performance visualization of complex JT models
- Geometric analysis and precise measurement on models
- Generation of exploded views and dynamic cross-sections
- Extraction of PMI information and metadata
- Bidirectional conversion between JT and other CAD formats
- Support for different levels of detail (LOD)
CADfix for repair and simplification of JT data
CADfix is an essential solution for ensuring the quality and usability of JT data, particularly important in exchange workflows and preparation for downstream analyses.
Specific capabilities include:
- Automatic detection and repair of geometric problems
- Controlled simplification of models to reduce complexity
- Mesh cleaning and facet optimization
- B-rep quality improvement to ensure accuracy
- Model preparation for simulation and analysis
- Conversion between different representations (facets, B-rep)
SimLab for creating immersive experiences
SimLab allows transforming JT models into immersive experiences for training, design reviews, or client presentations.
Its key features include:
- Creation of virtual environments from JT models
- Generation of high-quality photorealistic renderings
- Integration with virtual and augmented reality solutions
- Animation of mechanisms and assembly sequences
- Adding interactivity to technical models
- Easy sharing of 3D experiences via different platforms
CADIQ for model validationCADIQ for model validation
CADIQ is a specialized solution for CAD model validation that plays a crucial role in exchange processes and documentation of modifications (ECO).
Its main capabilities related to JT are:
- CAD derivation validation: comparison between the native CAD source model and data exported in JT
- Automatic generation of validation reports highlighting the accuracy of published data
- Identification of differences to determine if affected models can be used safely
- Revision comparison to automatically identify model changes during ECO approval
- Detection of unintentional or accidental changes, preventing undocumented modifications
DEXcenter for exchange automation
DEXcenter is a powerful platform for automating CAD data exchanges, including JT files, in complex enterprise environments.
Its key features include:
- Accessible web interface allowing easy access to all users
- Secure environment for transmitting sensitive proprietary CAD data
- Data encryption during transfer over the Internet
- Maintaining a detailed record of each exchange
- Automatic generation of Technical Data Packages (TDP) in 2D and 3D
- Automatic validation of 3D TDPs including PMI
- Possible integration with PLM systems
DEXcenter significantly improves the efficiency of CAD data exchanges, reducing time and resource waste by more than 80%, while ensuring compliance with regulations such as ITAR.
Best Practices for JT File Exchange
The efficiency of data exchanges in JT format relies on the adoption of best practices that ensure the quality, security, and usability of models.
Choosing the appropriate JT configuration
The JT format offers different configuration options that should be selected according to the specific needs of the exchange.
Important considerations for configuration:
- Level of detail (LOD): define chordal and angular parameters adapted to the intended use
- Inclusion or not of exact B-rep representation (XT B-rep)
- Definition of attributes conforming to company-defined rules
- Assembly structure appropriate for the target application
- Compression and optimization to balance size and quality
Quality validation procedures
Validation of JT files is essential to ensure they meet defined quality requirements and standards.
Recommended steps for validation:
- Verification of file compliance with JT specifications
- Control of geometric accuracy against the source CAD model
- Validation of attributes and metadata
- Verification of PMI presence and accuracy
- Use of tools like CADIQ to automate validation
- Documentation of validation results for future reference
Integration with PLM systems
Integration of the JT format in product lifecycle management (PLM) systems allows optimization of workflows and ensures data consistency.
Effective integration strategies:
- Configuration of automated workflows for JT generation and validation
- Synchronization of modifications between native CAD files and JT representations
- Establishment of version control policies for JT files
- Implementation of role-based access rules for JT data
- Use of solutions like DEXcenter to automate exchanges
- Integration with validation tools like CADIQ to ensure quality
JT data exchange in the supply chain
Using the JT format in exchanges with supply chain partners requires special attention to certain aspects.
Recommendations for external exchanges:
- Establishment of clear standards for exchanged JT files
- Definition of specific requirements for each partner or supplier
- Transmission of only necessary data to limit IP exposure
- Implementation of verification processes upon file reception
- Use of secure channels like DEXcenter for exchanges
- Detailed documentation of exchanges for traceability
Optimization of translation processes
Optimization of translation processes to and from the JT format is essential to maintain data efficiency and quality.
Best practices for translation:
- Establishment of standardized procedures to minimize errors
- Adoption of clear naming conventions to identify versions
- Documentation of export and import steps for translated data
- Translation of only necessary data to avoid large files
- Systematic verification of data after translation
- Process automation for large volumes of files
Conclusion: Industrial Applications and Evolution Perspectives
The JT format has established itself today as an essential CAD interoperability solution in multiple industrial sectors thanks to its versatility and efficiency.
Current applications and added value
The JT format demonstrates its relevance through various strategic applications:
- Facilitation of collaborative design reviews between teams using different CAD systems
- Creation of digital mockups (DMU) for spatial validation and interference detection
- Support for Model-Based Definition (MBD) initiatives through PMI integration
- Long-term archiving (LOTAR) ensuring access to technical data over decades
- Lightweight visualization on mobile terminals for field teams
- Technical basis for immersive experiences in virtual and augmented reality
These applications demonstrate the ability of the JT format to efficiently address CAD interoperability challenges in complex industrial environments, allowing companies to streamline their processes and accelerate product development.
Evolution perspectives
The future of the JT format looks promising with several anticipated development axes:
- Enhanced cloud integration: Evolution towards cloud-based collaboration access and processing solutions allowing universal access to JT data from any device
- Semantic enrichment: Increasing incorporation of intelligent and contextual data to facilitate process automation and advanced analysis
- Convergence with digital twins: Use of the JT format as an essential component of digital twin strategies, connecting design, simulation, and operational data
- Support for emerging technologies: Continuous adaptation to meet the needs of new additive manufacturing methodologies and advanced composite materials
- Artificial intelligence: Exploitation of JT models for machine learning and generative design optimization
The JT format, in constant evolution since its creation, will continue to adapt to the growing demands of Industry 4.0, reinforcing its role as an interoperability facilitator in multi-CAD environments. Its ISO standardization and wide industrial adoption give it a privileged position to accompany the digital transformation of design and manufacturing processes.
By leveraging the advanced solutions offered by CAD Interop, companies can today fully benefit from the potential of the JT format while preparing for future evolutions in technical data interoperability.
