How to customize your IFC models for efficient project management

Throughout the entire lifecycle of a work (from the design phase to maintenance and decommissioning), there may be a need to check or customize the information of the IFC model. In general, these operations are possible thanks to the use of a BIM authoring tool that allows access to and management of all the information in a 3D BIM model.

Currently, it is also possible to resort to other more accessible solutions, both in terms of cost and ease of use. We are talking about advanced IFC editor tools that allow you to view, manage, and modify any 3D model in IFC format directly online.

Let’s discover more in this article!

Editing geometric properties

Why customize the properties of the IFC model?

Customizing IFC models is an advanced practice in Building Information Modeling (BIM) that allows adapting the informational structure of the digital model to the specific needs of the project, organization, or data management process. The IFC format, developed by buildingSMART International, is neutral and oriented towards interoperability. However, the standardized nature of the format may require customization interventions to enrich the model with properties not provided in the basic schema or to optimize data management in multi-software environments.

The IFC file has the peculiarity of containing a series of data that concern not only geometry but also specific information related to all elements of the model, such as thermal data, fire resistance, data from structural calculations, and any other information deemed useful both during the design and construction phases as well as during maintenance. This aspect is very useful for optimizing information management.

A BIM model is also an information container in continuous evolution. Data can always be implemented over time or updated based on user needs.

The needs may be many, and it is difficult to identify them all, but below we indicate some as examples:

• Updating information
  During the various phases of the project (design, construction, management), data changes. It is therefore necessary to modify the IFC file to update properties, quantities, materials, or technical parameters.
• Correction of errors or inconsistencies
  When a model is exported from different software, errors or missing information may appear. Modifying the IFC file allows correcting these issues without having to recreate the model from scratch.
• Adding custom properties
  It is often useful to enrich the model with additional information (e.g., maintenance codes, energy data, or costs) for a more comprehensive management of the building’s lifecycle.
• Optimization for specific analyses
  Some simulation or verification tools require the model to contain specific data or structures. Modifying the IFC allows preparing it for structural, energy, or sustainability analyses.
• Ensuring compliance with OpenBIM standards
  Editing the IFC also serves to standardize the model to international standards and ensure compatibility with different software and platforms.
• Geometric Modifications
  Editing the IFC may also involve geometric modification of the model for small variations during construction or for other specific needs.

However, it is important to remember that for a correct openBIM process, all changes made to the document must always be tracked and validated.

Advantages of custom properties in IFC models

Adding custom properties (Property Sets or Pset) allows:

• integrating specific project information such as internal codes, maintenance data, energy performance, costs, or special materials;
• improving the traceability of information throughout the lifecycle of the work (design, construction, management, and demolition);
• ensuring consistency between disciplines (architectural, structural, plant engineering) through data standardization;
• ensuring management of the IFC file even for those who do not have a BIM authoring;
• supporting Facility Management and Digital Twin processes, where the level of information (LOI) must be updated and compliant with asset requirements.

How to modify the custom properties of IFC models

That said, how do you modify a 3D BIM model in IFC format? What is the easiest method to access all the data throughout the lifecycle of the work?

The best possible way is certainly to use a tool that does not require installation and can be used on any device. In fact, with an advanced IFC editor, you can work anywhere, just have a device (PC, tablet, and smartphone) with an internet connection and a common browser for navigation.

An example of this type of application can be usBIM.editor.

Now I will briefly indicate how to proceed with this application easily and quickly:

• access usBIM from any browser by entering your “My ACCA” account credentials;
• create a new folder and, within it, upload the IFC file to be modified;
• click on the screen-shaped icon next to the uploaded file and choose the Edit option;
• select the object of interest and modify the object’s information by clicking on Properties in the upper right;
• click on Edit attributes to modify the Name and Description of the selected entity;
• click on Edit properties to modify, delete, or add new properties to the selected entity;
• click on Edit classifications to modify the classification of the selected entity;
• read in the properties toolbox the changes made to the selected object.

Using 3D objects in the IFC model

Understanding the structure of IFC data

Editing IFC properties requires a precise understanding of the data structure of the format. An incorrect intervention can compromise the readability of the model by other software or violate compliance with OpenBIM standards.

• Definition and objective

The IFC schema is a standardized data model, vendor-agnostic, developed by buildingSMART International for the construction sector, and is established as an international standard.

Its purpose is to describe in a logically structured way:

• the identity and semantics of objects (e.g., name, unique identifier, type/function)
• the characteristics or attributes of objects (material, color, physical performance)
• the relationships between objects, concepts, processes, and people (e.g., spatial position, connections, properties).

In practice, an IFC file is not just 3D geometry: it is a combination of objects, properties, and relationships.

• Hierarchical structure of the schema

The IFC schema is organized into layers or conceptual subdivisions that facilitate the extension, specialization, and management of data. This stratification helps understand where to modify, how to extend, without compromising compatibility.

• Entities, attributes, and relationships

In simple terms, entities define the objects that make up the model: for example, IfcWall, IfcDoor, IfcBuilding, etc.

Each entity derives from a definition in the EXPRESS schema and can be an instance (occurrence) or a type (type) depending on the modeling.

Each entity has attributes that describe intrinsic characteristics – e.g., name, description, GUID, position, dimensions, material. Some attributes are mandatory, others optional. For example, IfcRoot introduces attributes such as GlobalId, OwnerHistory, Name, Description.

It is essential that the attributes maintain semantic consistency when modifications are made.

Relationships connect entities to each other, establishing logical and spatial connections. Examples:

• IfcRelAggregates: hierarchical structure (e.g., building > floors > spaces)
• IfcRelDefinesByProperties: assignment of a property set to an object
• IfcRelContainedInSpatialStructure: insertion of an object into the spatial structure (e.g., a door in a wall in a floor)

Properly managing relationships is essential because the loss of a relationship can compromise the integrity of the model.

• Spatial structure and containment

The spatial structure defines “where” objects are located and how they logically group together. Typical elements of the spatial hierarchy:

• IfcProject: the project unit
• IfcSite: site/land
• IfcBuilding: building
• IfcBuildingStorey: floor
• IfcSpace: rooms/internal spaces.

Construction and plant objects are inserted into this structure through relationships.

• Properties and property sets (Psets)

Objects must contain informative data that describe their specific characteristics: this is where Property Sets (Pset) come into play. A Pset is a grouping of properties. These sets contain typical properties for that class of objects.

It is also possible to extend the schema to add custom Psets, but this must be done in a consistent and documented manner.

• Geometry and representation modes

The IFC schema supports the geometric representation of the object (shape), but also multiple and alternative modes. E.g.: extruded solids, mesh, bounding boxes.

When modifying an IFC file, it is necessary to consider that interventions on geometry may have repercussions on properties and relationships (position, collisions, spatial belonging).

• Schema versions and serialization

It is important to check which version of the schema you are working with (e.g., IFC2x3, IFC4, etc.) because each version introduces new entities, properties, and rules.

Ensuring OpenBIM compliance

OpenBIM compliance is the cornerstone of interdisciplinary collaboration based on open standards. Ensuring that an IFC model complies with such standards means ensuring:

• total interoperability between different software;
• data transparency throughout the entire lifecycle of the project;
• traceability and reliability of shared information.

Compliance checks include:

• validation of the IFC schema with IFC checker and IDS BIM tools;
• checking mandatory Psets required by information specifications;
• analysis of the MVDs (Model View Definitions) relevant to the workflow.

Ultimately, a compliant and correctly customized IFC model represents a guarantee of interoperability and informational quality in any open BIM ecosystem.

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