IFC 5: What it is and how to manage the new openBIM standard for data exchange in the AEC sector

IFC 5 represents the next generation of the Industry Foundation Classes (IFC) standard, aimed at simplifying and improving data exchange in the architecture, engineering, and construction (AEC) sector. It arises from the need to overcome the complexities and limitations of previous versions of IFC, such as IFC 4, opening new possibilities for collaboration, automation, and integration with emerging technologies like Universal Scene Description (USD).

To manage the new openBIM standard from buildingSMART International, ACCA has developed a specific viewer for IFC 5 that allows conversion from previous versions of IFC to the new standard and:

• the visualization of large files (buildings and infrastructures);
• the visualization of the historical values of properties to experience “dynamic” USD flows;
• the visualization of the IFC 5 model on usBIM.geotwin.

To preview the new tool, you can book your free version by leaving your request.

usBIM.ifc5: A Revolutionary and Free IFC5 Viewer

usBIM.ifc5 is a game-changing tool designed to accelerate the evolution and adoption of the openBIM IFC5 standard, currently under development by buildingSMART International. Developed by ACCA software, this cutting-edge solution provides a seamless environment for managing and visualizing IFC models of any scale and complexity.

Unlike conventional IFC viewers, usBIM.ifc5 goes beyond simple model visualization. It actively contributes to the testing and implementation of the IFC5 standard, offering an advanced set of tools to enhance digital workflows in the IFCx format.

IFC 5 model of the Bisantis Viaduct Catanzaro

Key features of usBIM.ifc5

usBIM.ifc5 is more than a viewer—it introduces revolutionary capabilities that set a new standard for IFC-based workflows:

• Non-destructive editing: Modify models safely while preserving original data integrity.
• Real-time collaborative editing: Multiple users can edit models simultaneously, enhancing teamwork and efficiency.
• GIS integration: Seamlessly connect IFC models with geospatial data for advanced infrastructure planning.
• Model federation: Manage and coordinate complex projects effortlessly by integrating multiple IFC models.
• Advanced spatial boundary analysis: Optimize spatial relationships and infrastructure management, including borehole data.
• Continuous updates: Stay ahead with ongoing improvements aligned with the evolving IFC5 standard.
• Community-driven innovation: Engage with other users through a dedicated forum to share feedback and best practices.
• USD (Universal Scene Description) compatibility: Bridge IFC workflows with cutting-edge digital modeling technologies.
• High-performance web-based interface: Access models effortlessly from any device without installation.

Seamless integration with the usBIM ecosystem

usBIM.ifc5 is a core component of the usBIM ecosystem, ensuring full compatibility with BCF, IDS, and bSDD standards. This guarantees seamless compliance with openBIM workflows and unlocks additional functionalities for BIM professionals.

Experience the future of IFC5 for free

During the testing phase, ACCA software is offering usBIM.ifc5 completely free of charge. This is a unique opportunity for industry professionals to explore the next generation of BIM interoperability and contribute to shaping the future of the IFC5 standard.

With usBIM.ifc5, ACCA software not only supports the validation and implementation of IFC5 but also empowers professionals and organizations to stay at the forefront of openBIM innovation.

Let’s now delve deeper into the objectives, benefits, and key concepts of IFC5.

To learn more, read also: Converting a 3D model into an IFC format

Example of displaying the data structure of a BIM model in IFC 5 format

Key Objectives and Benefits of IFC 5

IFC 5 introduces a series of improvements and new features compared to previous versions of the standard, making it a beneficial choice for data exchange in the AEC sector. Here are some of the main reasons to use IFC 5:

• simplification and ease of implementation: IFC 5 has been designed to be simpler to implement and manage compared to previous versions, such as IFC 4. Its structure has been streamlined, focusing on simple geometry and a reduced number of initial classes and properties, which reduces complexity and the time required for implementation. The goal, at least in the current phase of development, is to enable developers to implement IFC 5 in a few days, unlike the months or even years required for previous versions. In the current version of IFC, still under development, concepts that could have increased the time needed for implementation without a real final benefit have been deliberately excluded. The aim is to make the format immediately operational for a wide number of stakeholders and to understand their issues by limiting the number and complexity of concepts to implement;
• greater interoperability and collaboration: IFC 5 aims to improve interoperability between different software and disciplines, allowing for a smoother and more continuous workflow. Its modular structure, with a core and optional modules, allows the standard to be tailored to the specific needs of different sectors and use cases. Additionally, it facilitates multi-author collaboration, enabling multiple users to contribute to the same dataset without conflicts;
• support for new use cases: IFC 5 has been designed to support a broader range of use cases, including BIM, GIS, analysis, project version management, and integration of non-modeled data such as point clouds. This versatility makes IFC 5 a standard more suited to the evolving needs of the AEC sector;
• potential integration with USD: IFC 5 could be integrated with Universal Scene Description (USD), a framework for describing complex 3D scenes developed by Pixar. USD offers features such as managing large models, composing data from multiple authors, and incremental change management. Integration with USD could lead to greater interoperability, more efficient workflows, and new opportunities for analysis and visualization;
• JSON serialization: IFC 5 uses JSON as its primary serialization format. JSON is a readable, flexible, and widely supported format, which facilitates data exchange and processing.

The benefits of IFC 5

IFC 5 and USD: two distinct standards

The integration of some principles and features of Universal Scene Description (USD), developed by Pixar, is one of the technological implementations of the new IFC 5. IFC 5 and USD are and will remain two distinct standards. It cannot be said that IFC 5 will coincide with USD, but it will simply borrow some basic characteristics from this technology, as will happen for other existing data structures.

IFC and USD are two distinct standards, with different goals and characteristics:

• IFC 5 is the next generation of the IFC (Industry Foundation Classes) standard, specifically designed for the AEC (Architecture, Engineering, and Construction) industry. Its main goal is to improve interoperability and collaboration among the various software and disciplines involved in the life cycle of a building;
• USD (Universal Scene Description) is an open-source standard developed by Pixar for the description and interchange of complex 3D scenes, primarily used in the visual effects industry.

Some basic principles of USD may be utilized in the new IFC 5 to facilitate the management of large-scale models, the composition of data from multiple authors, and the management of incremental changes.

The relationship between IFC 5 and USD (Universal Scene Description) offers a new perspective on interoperability and technological integration in the AEC (Architecture, Engineering, and Construction) sector. It is not a matter of overlap or replacement: IFC 5 and USD can be seen as “siblings,” each with a unique role. IFC 5, while incorporating some concepts and terminology from USD, has been specifically designed to address the specific needs of the industry. This makes it not an extension or replacement of USD, but a complementary solution, with distinct goals and characteristics.

For example, IFC 5 addresses complex use cases that USD alone cannot satisfy, such as the management of typically defined objects and their multiple reuse in projects (the concept of “type/instance” in the classic IFC structure), a fundamental approach for modularity and scalability in AEC projects. Furthermore, the data structure of IFC 5 has been designed to ensure greater flexibility compared to the more rigid model of USD. While USD adopts a “top-down” approach to data composition, IFC 5 allows for a more “bottom-up” construction, essential for adapting to the iterative and collaborative nature of the construction industry. Another crucial difference lies in the serialized format: USD uses a specific binary file format, while IFC 5 adopts JSON, which allows for direct integration and greater compatibility with both dedicated IFC 5 runtimes and those based on OpenUSD.

This hybrid approach not only enhances the adoption of IFC 5 due to its ability to be represented through USD, but also unlocks advanced use cases such as high-quality rendering, management of digital twins and other advanced simulations. In this sense, IFC 5 positions itself as a fundamental pillar for the future of openBIM, ensuring that AEC projects keep pace with technological innovation while remaining focused on the specific needs of the industry.

IFC5 and USD: shared concepts, but distinct and autonomous standards

Official communication from buildingSMART International illustrating the relationship between USD and IFC 5

An exploration of the key concepts of the IFC 5 file

Defining what an “IFC 5 file” is complex, as the very concept of a file is evolving within the development of IFC 5. There is a transition towards a component-based approach and JSON serialization, which could lead to different implementations and representations of the data.

IFC 5 moves away from the traditional representation of an IFC model as a single monolithic file. Instead, it adopts a component-based approach, where objects are broken down into smaller, independent parts. These components can be flexibly combined and reused to create different representations of a model:

• components: the approach will be of the “ECS” (Entity Component System) type, where an entity (like a wall) is defined by the combination of different components (geometry, materials, properties). This approach is similar to that used in video games, where a character is composed of components such as 3D model, animations, and statistics;
• JSON serialization: IFC 5 will adopt JSON as the main format for data serialization. JSON is a human-readable, flexible, and widely supported text format that facilitates data interchange and management.

The role of USD’s basic concepts: a flexible foundation for IFC 5

As previously mentioned, one of the important innovations of IFC 5 is the use of Universal Scene Description (USD).

The basic concepts of USD offer advanced capabilities for managing large datasets, multi-author collaboration, and composing data from different sources:

• Prim and Prim Spec: USD uses the concept of “Prim” (primitive) to represent elements of a scene. A “Prim Spec” is a specification for a Prim, defining its properties and attributes. IFC 5 could use Prim Spec to define the components of objects;
• Layers: USD employs a “layers” system to compose data from different sources. This allows for incremental information to be added to a model without altering the original data. IFC 5 could use layers to manage multi-author collaboration and different versions of a model.

Some basic concepts of USD taken in IFC 5

Implications for the Concept of “File”

The adoption of a component-based approach and the potential integration with USD make it difficult to define exactly what an “IFC 5 file” is due to:

• multiple representations: IFC 5 data could be represented in various ways, such as JSON files, USD files, or databases;
• dynamic composition: the composition of IFC 5 data could occur dynamically, combining components from different sources at the time of model loading.

How do USD principles facilitate multi-author collaboration?

One of the key features of Universal Scene Description (USD) is the layer system that allows multiple authors to contribute to a project without overwriting each other’s work.

The USD layer system can be imagined as a series of overlapping transparent sheets. Each layer can contain information about Prim, the basic elements of a USD scene. This information includes geometry, materials, textures, and other attributes. This allows for:

• non-destructive editing: layers allow a model to be modified non-destructively. An author can create a new layer and make changes without altering the original data. If necessary, the layer can be removed or modified without affecting other layers;
• merging contributions: layers are combined to create the final scene. USD intelligently manages layer overlaps, resolving any conflicts between information present on different layers;
• change tracking: each layer is associated with an author, allowing tracking of who made which changes. This is crucial for version management and collaboration in large teams.

In addition to layers, USD uses the concept of Prim Spec (short for “Prim specification”) to define the information associated with a Prim. A Prim Spec can be of three types:

• define: creates a new Prim;
• over: overwrites or adds information to an existing Prim;
• class: defines a Prim as a “class,” meaning a reusable model.

Using Prim Spec in combination with layers allows for granular collaboration management. For example, an author can create an “Over” Prim Spec on a layer to modify only a specific attribute of a Prim without having to redefine the entire Prim.

The USD layer and Prim Spec system offers several advantages for multi-author collaboration:

• parallelization of work: multiple authors can work simultaneously on different aspects of the same project without interfering with each other;
• efficient change management: changes are managed at the layer level, simplifying the review, approval, and integration of contributions from different authors;
• flexibility and control: authors have granular control over changes, being able to modify only specific attributes of a Prim without having to redefine the entire object;
• traceability and accountability: the layer system allows tracking the origin of each change, ensuring accountability and transparency in the collaboration process.

Modifying Data in IFC 5: A Component-Based and Flexible Analysis

The question of whether it is possible to modify an “IFC 5 file” opens an interesting discussion about the unique characteristics of this evolving standard. As highlighted earlier, IFC 5 adopts a component-based approach and potential integration with USD, making the concept of “file” less rigid and opening new possibilities for data modification.

IFC 5 breaks down objects into independent components, offering finer granularity for data modification. Instead of modifying an entire object, it is possible to modify individual components such as geometry, materials, or properties. This flexibility allows for targeted changes without affecting other parts of the object.

Here are some concrete examples:

• modifying geometry: instead of recreating the entire geometry of a wall, one could modify the geometric component to add an opening for a window;
• updating materials: one could replace the material component of a floor without having to remodel the entire floor;
• adding properties: new components could be added to include additional information, such as fire rating data.

Modifying data in a component-based system requires careful management of the relationships between components. For example, modifying the geometry of a wall may require updating connections with other objects, such as doors or windows. Integration with USD introduces further challenges, such as managing conflicts between layers and synchronizing changes among different authors.

Moreover, the evolution from IFC 4 to IFC 5 represents a significant change in how building model data is structured, managed, and exchanged, as an additional challenge, it should be noted that the transition from IFC 4 to IFC 5 will require time and effort to ensure compatibility with existing data and software.

IFC5 and Interoperability Between Software

How does IFC5 improve interoperability between software? This question focuses on a crucial aspect of this evolving standard. IFC5 addresses interoperability challenges by introducing a series of significant changes compared to IFC 4:

Reduction of Complexity and Modularity
A key factor in improving interoperability is the reduction of complexity. IFC5 aims to simplify the standard by focusing on a core of essential functionalities and adopting a modular approach. This means that software developers can implement only the parts of IFC5 relevant to their specific use cases, reducing workload and the possibility of errors.

• IFC5 is divided into a core and domain extension modules. This modular approach allows developers to focus on essential functionalities, adding specific modules only when necessary;
• IFC5 will start with a reduced version, which includes only the minimum essential functionalities. This iterative approach facilitates the implementation and validation of the standard.

Structure and modular approach for the development of the new IFC 5

JSON Serialization Format

The adoption of JSON as the primary serialization format contributes to interoperability, as JSON is a human-readable, widely supported, and flexible format.

• Goal of having a single serialization for IFC 5, simplifying data exchange between different platforms.
• Simple JSON format that can be easily validated, ensuring data consistency and correctness.

Standardization and Predictability

IFC 5 aims to establish a more rigorous standardization, reducing ambiguity and ensuring that there is only one correct way to represent the data.

• Goal of having a single method for object placement, eliminating confusion and incompatibilities.
• Need for predictable processing of IFC 5 data by the receiving software, ensuring that the data is interpreted correctly.

Integration with Existing Standards

IFC 5 promotes interoperability by integrating with existing standards, such as USD, rather than reinventing the wheel. This allows leveraging the advanced features of these standards for data management, collaboration, and visualization.

• Ability to use USD as a basis for IFC 5, paving the way for greater interoperability with USD-based tools and workflows.
• IFC 5 includes the ability to reference third-party data, such as point clouds, facilitating integration with other data sources.

Standard API

The development of a standard API (Application Programming Interface) for IFC 5 will facilitate access to and processing of data by different software. A well-defined API allows developers to create applications that interact with IFC 5 data in a consistent and reliable manner.

IFC 5 Viewer with example of BuildingSmart International data structure

The release date of IFC 5: an evolving unknown

Despite the intense research and development activity surrounding IFC 5, there is no precise release date. However, we can highlight interesting insights into the development process and the possible timeline.

IFC 5 will be released incrementally, starting with a “reduced” version with basic functionalities. This initial version will be followed by updates and additional modules that will extend functionalities over time.

This approach aims to facilitate initial adoption, allow for gradual fine-tuning through user feedback, and manage complexities more easily.

A possible development timeline includes:

• internal testing: an initial testing phase with a small group of users to assess the stability and functionality of the reduced version of IFC 5;
• public beta: a public beta release to gather feedback from a broader range of users and identify any issues or areas for improvement;
• IFC 5 (Release): the official release of the first version of IFC 5, with basic functionalities and support for fundamental use cases;
• development of the IFC 5 API: a phase dedicated to the development of the API for IFC 5, which will facilitate integration with other software and platforms;
• subsequent releases: updates and additional modules that will expand the functionalities of IFC 5 over time, including support for new use cases, more complex geometries, and integration with other standards such as IDS and BCF.

IFC 5 and the future of openBIM for the AEC sector

The path to IFC 5 represents one of the most significant transitions in the history of digital interoperability for the AEC sector. It is not merely a technical update, but a radical transformation aimed at redefining how information is exchanged, used, and valued. At the heart of this evolution is the need to embrace semantics as a cornerstone: an IFC 5 that simplifies without losing the depth of information and enables smoother collaboration among heterogeneous disciplines.

The success of IFC 5 will depend on its ability to meet the needs of a rapidly changing sector, where digital twins, artificial intelligence, and data-driven management are becoming increasingly central. The challenge will be to maintain a balance between technological evolution and continuity with existing systems, fostering a transition that is not only innovative but also inclusive and sustainable.

With a more flexible structure, supported by advanced semantic approaches and better integration with modern formats like JSON and emerging technologies like USD, IFC 5 has all the right elements to become the cornerstone of digitalization in the AEC sector. However, the path to global adoption will require unprecedented collaboration among developers and stakeholders at every level.

IFC 5 not only represents the future of data exchange but also an opportunity to build a more connected, efficient, and resilient sector. It is a standard that promises not only to address today’s challenges but also to anticipate and lead those of tomorrow, laying the groundwork for a digital ecosystem where semantic richness and interoperability are at the heart of every innovation.

Manage the new openBIM standard from buildingSMART International with the IFC 5 viewer from ACCA. Try usBIM.IFC5 for free