What information can be managed with the IDS standard?

In recent years buildingSMART has developed a new standard that aims to define the requirements of the information to be exchanged in a BIM order, in a format that can be interpreted by the computer.

What information in particular is handled with the IDS standard? How to create an IDS file to manage information exchanges?

I remind you that you can use an IDS BIM – Information Delivery Specification application to take full advantage of this powerful standard and work much faster.

The IDS standard in the openBIM workflow

Understanding the IDS Standard in the openBIM Workflow

The IDS (Information Delivery Specification) standard represents one of the key tools introduced by buildingSMART International to improve the management and exchange of information in openBIM projects. It is an open format that allows for the structured and readable definition, verification, and validation of information requirements related to IFC models, understandable by both humans and software.

In the openBIM workflow, the IDS acts as a bridge between the client’s information requirements and the data actually provided in the BIM model. This standard allows for the establishment of which information must be included, in what format, and to which elements of the model they should be associated. This way, every phase of the project (from design to construction and up to building management) can rely on consistent, verifiable, and interoperable data.

Thanks to the IDS, organizations can:

• reduce interpretation errors in information requirements;
• automate the validation process of IFC models;
• improve collaboration among different professionals and software;
• ensure greater transparency and traceability of information throughout the project lifecycle.

What information can be handled with the IDS standard

In a BIM order, the information added to the 3D model are defined by the client who, at the initial stage of the project and according to his needs, has the responsibility of establishing the type, timing and methods of exchange of the data: the so-called Exchange Information Requirement (EIR).

The IDS standard is precisely the document that contains all these information exchange requirements.

It’s defined by buildingSMART International as a fundamental component in the management of the BIM process that can be used as contract basis for the correct delivery of the required information.

The IDS standard is nothing more than a computer-readable file, necessary both in the modeling phase and in the validation phase of IFC models and with the aim of making the entire exchange workflow much simpler, efficient and reliable.

Basically, it is the standard that defines the type of information and the way exchangeing it in an openBIM process. It guarantees that the information are correct but does not verify the correctness of the entire BIM model. However, any subsequent verification of the model will certainly benefit from the IDS process as it makes possible to determine in advance the existence and validity of certain information.

Here is what information can be controlled by the IDS standard:

• IFC attributes (“Name”, “Description”);
• IFCtype;
• properties (“Pset”);
• quantity;
• classifications;
• composition;
• materials.

Validation Rules Supported by IDS

With dedicated software tools it is also possible to carry out checks on the IFC file, in order to verify whether the requirements set out in the IDS have been met.

Verifications can be carried out according to the following rules:

• existence (does the property exist?);
• equality (does a specific attribute have a certain value?);
• limits (is the value between two limit values?);
• enumerations (does the value exist in a defined list of items?);
• measure (the value of a given attribute or property has been defined as IfcLengthMeasure).

To learn more about the IDS standard, also read “IDS: what is it and what is it for” and “The difference between the IDS standard and IFC or MVD“.

Furthermore, I also recommend reading the in-depth article: “openBIM standards“.

How to Manage Information Exchange with IDS

To manage the information exchange among the actors of a BIM project (client, designer, contractor, supplier, validator, etc.), an IDS BIM tool is necessary to:

• create the IDS document with all the information specifications (editor);
• guided editing of the specifications requested by the client (modeler);
• validate the datasets delivered in standard IDS format (validator).

How does it work?

Phase 1: Create the IDS Document

You can create the document to define all the information delivery specifications and easily transform it into a standard IDS file to be used in the modeling and validation phases of IFC models.

Phase 2: Apply the IDS to the BIM Model

Once the creation phase is complete, the IDS file is delivered by the client to the modeler.

The IDS modeler of usBIM.IDS identifies in the IDS document the information structure defined in the project specifications and automatically associates it with the IFC model. This way, you obtain a single IFC file containing not only the geometric data but also all the data required by the client.

Phase 3: Validate the IFC File

Finally, we move on to the data validation phase:

• import the IFC file to be validated or, if necessary, create the federation of multiple IFC files;
• select the IDS file;
• check all the requirements specified in the IDS file and validate the IFC file.

Invalid IFC elements in the project are flagged, and you can monitor all reported issues on dedicated dashboards with reports and statistics.

Benefits of Managing Information with the IDS Standard

One of the main advantages of the IDS is the clarity in defining information requirements. Every BIM project requires the management of a large amount of data: from the technical characteristics of construction elements to information on materials, energy performance, or maintenance. Thanks to the IDS, these requirements are described clearly and precisely, avoiding subjective interpretations and misunderstandings among the various project actors. Everyone knows exactly what information needs to be provided, in what format, and to which elements of the model they should be associated.

Another significant advantage concerns the automatic validation of IFC models. The IDS allows for quick and automatic verification of whether the model contains all the required information, without resorting to complex and costly manual checks. This improves quality control and allows for immediate identification of any errors or omissions, reducing the risk of problems in the later phases of the project.

From a collaboration standpoint, the IDS promotes greater interoperability among different software and platforms. As it is an open standard, it can be used by all professionals regardless of the BIM tools employed. This aspect is crucial for ensuring a truly openBIM workflow, where architects, engineers, builders, and building managers can share and exchange data smoothly and without technological barriers.

Managing through IDS also makes the exchange of information more efficient and faster. Each IFC model can be compared with the information requirements established in the IDS document, allowing for automatic validation of data compliance and avoiding continuous revisions or corrections.

An additional strength is the transparency and traceability of data. The IDS clearly documents which information has been requested, delivered, and approved, creating a sort of digital “chain of custody.” This increases trust among the parties involved and also facilitates reporting and contractual management.

Looking at the long term, the IDS standard proves useful not only during the design or construction phases but also in the management and maintenance phase of the building. Having structured, consistent, and verified data facilitates the creation of accurate digital twins, useful for monitoring the performance of the property over time and planning interventions more effectively.

Finally, all these benefits translate into a reduction of costs and risks. Fewer errors, fewer delays, less ambiguity: the result is a leaner, more reliable, and cost-effective process.

Case Study: Verifying the Informational Requirements of an IFC Model with IDS

The use of the IDS standard allows transforming the informational requirements needed for a BIM model into specifications readable by both the operator and the software, and to use them to automatically verify the compliance of an IFC model. The case study analyzed shows how IDS specifications can be progressively articulated to check different characteristics of the model’s objects, ultimately leading to automatic validation and management of non-conformities.

From Defining Requirements to IDS Specification

An IDS specification consists of a description, a scope of applicability, and one or more requirements. The description identifies the requirement related to the project, while the applicability identifies the IFC entity to be checked, and the requirement establishes the value that a particular characteristic must assume. Applicability and requirements are built through the so-called facets, which are characteristics of the entities within the IFC schema used as criteria for selection and verification.

Facets can be combined to make the checks progressively more specific. Among those used in the example are facets relating to entities, attributes, classifications, properties, materials, and relationships. In applicability, facets allow filtering the model objects on which to perform the check; in the requirements, they define the conditions that such objects must meet.

The system allows, for instance, identifying all entities of the IFC Window class that possess a specific value in the Description attribute and subsequently request that they have a certain Predefined Type, such as Skylight. Another check can relate to elements of the IFC Space class, where it simply requires that the Long Name attribute is present and valued, without imposing specific content.

The same logic can be applied to properties. In the case of Standard-type IFC Wall entities, the requirement can impose the presence of a specific property belonging to a specific Property Set and require, for example, that the corresponding boolean value is true. Similarly, it is possible to check materials: IFC Slab elements identified by a certain description can be subject to a requirement mandating the presence of a specific material. In this case, IDS simplifies the material check by verifying its name regardless of how the relationship with the material has been structured in the IFC model.

Classifications and Relationships Between Objects

Facets also enable the verification of the use of classification systems. An element can be filtered by IFC class and, among the requirements, it can be requested that it has a certain classification identified by name and code. This allows for checking, for instance, the belonging of a category of objects to a classification system such as ETIM.

An additional level of control concerns IFC relationships. In the example, the objects of the IFC Furniture class characterized by a specific property that identifies tables with chairs must belong to a group. The requirement is expressed through the Part Of facet by selecting the RelAssignsToGroup relationship.

The ability to combine multiple facets also allows building complex requirements. For an entity of the IFC Site class, for instance, it is possible to simultaneously request a specific value of the RefElevation attribute, a certain Total Area, and a building height limit. This way, the IDS specification does not merely verify the presence of a piece of information, but can simultaneously check multiple characteristics of the same entity.

Mandatory, Optional Requirements and Prohibitions

A particularly significant aspect of the standard is the management of cardinality, which allows establishing whether a certain type of information must necessarily be present, may be present, or must not be present in the model.

In applicability, it is therefore possible to specify that the model must contain, may contain, or must not contain certain entities. If, for example, a specification establishes that the model may contain Standard-type IFC Wall, the absence of such elements does not generate an error; if, however, the same condition is defined as mandatory, their absence is flagged by the validator. Conversely, setting the condition as negative means that the presence of those elements constitutes a non-conformance.

Cardinality can also be used in requirements. In the example related to spaces, some properties – such as Handicap Accessible and Publicly Accessible from the Property Set Space Common – are defined as optional. The requirement does not impose their presence but indicates to the modeler the opportunity to use these properties to represent certain functional information of the environments.

Pattern control, intervals, and complex values

IDS allows going beyond simple equality checks between an expected value and the one present in the model. The parameters of the facets can use both single values and complex values, such as enumerations, numerical ranges, and patterns.

An example concerns the naming of doors. It is possible to establish that the name of a door must follow a certain pattern, for example, the word door followed by a space and a sequence of 4, 5, or 6 numbers. The check is expressed through a regular expression; the filling can be supported by artificial intelligence tools that help generate the pattern to be inserted into the IDS specification based on the description of the rule.

For numerical values, it is possible to define ranges and comparison operators. In the case of spaces, for example, a property relating to height can be set so that the value is greater than or equal to 3 m. Similarly, it is possible to verify that the area of certain environments, such as bathrooms, exceeds a predetermined threshold.

The standard also allows checking the length of textual values. For doors, it can be imposed, for example, that the Name attribute does not exceed 20 characters, while for the description of an IFC Project entity, a minimum length of 35 characters can be established. In this case, the check does not refer to a geometric characteristic of the element, but solely to the number of characters contained in the attribute.

The link with the BuildingSMART Data Dictionary

The definition of requirements can be further supported by the BuildingSMART Data Dictionary (bSDD), an online service that collects dictionaries of terms organized by classes and linked to IFC classes, their properties, allowed values, units of measurement, translations, and relations.

The bSDD hosts national and international classification systems, domain classifications, and systems developed by heritage entities or private companies. In the context of compiling an IDS specification, the connection between the two systems can be made through a URI, which uniquely identifies the external resource associated with the property. The URI does not necessarily have to point to the bSDD, but can refer to another external resource used to describe that specific information.

The operational advantage emerges when searching for a property directly in the bSDD while filling out the specification. Once the property associated with the desired classification and code is identified, it can be imported into the IDS, automatically transferring information such as property name, Property Set, type, allowed values, and any constraints. This reduces the risk of errors in the manual filling of requirements.

Validation of the IFC model

Once the specifications are defined, the IFC model can undergo a BIM validation process. The verification can be performed by the contractor during the information production phase, to check the model before delivery, or by the client during the technical review of the project, to ensure that what is delivered complies with the agreed requirements.

The validator reads the IDS file, identifies in the model the entities included in the scope of applicability, and checks for each of them compliance with the set requirements. In the absence of errors, the model passes validation and can proceed to the next phases of the approval process. In the presence of non-conformities, however, the reports must be analyzed and managed before repeating the check.

The concrete case: checking IFC Roof elements

Suppose that a specification is defined in an IFC model that requires IFC Roof class entities to meet two conditions: to have a certain property with a value less than or equal to 0.27 and to have a specific classification code.

At the end of the validation, eight reports are found. One element passes both checks: the classification code is present, and the property value is 0.2, which is less than the threshold of 0.27. For the other elements, however, the classification is correct, but the property has a value of 0.3, which exceeds the allowed limit. The validator then highlights the non-conformity and allows selecting the element directly in the 3D model, facilitating the identification of the concerned object.

The correction can be made directly in the model editing environment by modifying the property value. Even at this stage, the system checks compliance with the IDS constraint: entering a value like 0.4 is rejected because it does not meet the condition ≤ 0.27, while a compliant value is accepted.

Alternatively, the identified issues can be exported in BCF (BIM Collaboration Format) and shared with the modeler or the person responsible for the correction. The BCF, another open standard from buildingSMART International, allows managing and communicating the issues identified during the various phases of the BIM process. The flow then becomes iterative: validation, identification of non-conformities, communication of issues, model correction, and new validation, until compliance with the requirements is achieved.

Considerations and limits of the IDS standard

The case study highlights how IDS allows formalizing and automating a significant portion of the information checks on IFC models, combining applicability criteria and requirements and using different types of facets, cardinality, and constraints on values.

At the same time, the analyzed IDS version 1.0 has some limitations: it is mainly focused on verifying the information and main relations of IFC entities and does not allow, as described in this intervention, geometric checks, checks based on calculated or dynamic values, checks referring to external data to the IFC model, or validations based on IFC relations specific to a particular domain. These aspects are indicated as possible areas for evolution in future versions of the standard.

Finally, the case confirms that the effectiveness of an IDS validation procedure depends not only on the software used but also on the correct setting of requirements and knowledge of the IFC standard, which is considered essential for professional use of the IDS standard.

How to create an IDS file

To create or edit an IDS format document with all the information specifications, you need to use an IDS editor.

usBIM.IDS editor is a free, online tool that enables you to create and edit an IDS file, the document that collects and defines all the information delivery specifications, which is also necessary to deal with the modeling and validation stages of an IFC model.

Thanks to the IDS file, you can enjoy all the advantages offered by this format and can:

• define the information specifications in an intelligible way by operators and software structures;
• enter all useful information to facilitate the understanding of your request;
• generate an output related to the IFC model to allow automatic validation of the model with respect to the requirements.

Watch the video that shows you all the steps to obtain an IDS file according to bSI guidelines.

FAQ about the IDS Standard

What is the IDS standard and what is its role in the openBIM workflow?

The IDS (Information Delivery Specification) standard represents one of the key tools introduced by buildingSMART International to improve the management and exchange of information in openBIM projects. It is an open format that allows for the structured and readable definition, verification, and validation of information requirements related to IFC models, understandable by both humans and software. In the openBIM workflow, the IDS acts as a bridge between the client’s information requirements and the data actually provided in the BIM model, establishing which information must be included, in what format, and to which elements of the model they should be associated. This ensures consistent, verifiable, and interoperable data at every stage of the project.

What types of information can be managed with the IDS standard?

In a BIM project, the information added to the 3D model is outlined by the client through the Exchange Information Requirement (EIR). The IDS standard is the document that collects all these requirements and defines the methods and timing of exchange. It can contain specifications on IFC attributes (‘Name’, ‘Description’), type of IFC (IFC 2×3, IFC 4, etc.), properties (‘Pset’), quantities, classifications (UNICLASS, OMNICLASS, etc.), composition, and materials. It is therefore the tool that defines the way and type of information to be exchanged in an openBIM process, ensuring that the data is correct and consistent with the client’s requests.

What validation rules does the IDS standard support?

With specific software tools, it is possible to verify whether the IFC models comply with the requirements defined in the IDS. The validation rules include: existence (checks that the property exists), equality (an attribute has a specific exact value), limits (the value is within two limits), enumerations (the value belongs to a defined list of items), and measure (the value of an attribute or property is defined as IfcLengthMeasure).

How to manage information exchange with the IDS standard?

To manage the information exchange among the actors of a BIM project, an IDS BIM tool is necessary that allows for the creation, application, and validation of IDS documents. The process involves three phases: Phase 1, creation of the IDS document, where all the information delivery specifications are defined and a standard IDS file is generated; Phase 2, application of the IDS to the BIM model, where the file is automatically associated with the IFC model; Phase 3, validation of the IFC file, where all specified requirements are checked, and any non-compliant elements are identified through reports and control dashboards.

What are the benefits of managing information with the IDS standard?

The adoption of the IDS standard offers numerous advantages: clarity in defining information requirements, automatic validation of IFC models, greater interoperability among different software and platforms, efficiency in data exchange, and transparency in information management. Additionally, it allows for better data traceability and a reduction in costs and risks due to faster and more reliable processes. The IDS standard is also useful in the management and maintenance phases of the building, as it allows for the creation of accurate and updated digital twins, improving monitoring and planning of activities.

How to create an IDS file?

To create or modify a document in IDS format, it is necessary to use an IDS editor. usBIM.IDSeditor is an online and free tool that allows you to create and modify the IDS file, collecting and organizing all the information specifications of the project. With this file, it is possible to clearly define the requirements that the project must meet, include all useful information to facilitate understanding of the request, and generate a file relatable to the IFC model to allow for automatic validation against the established requirements. You can also follow a video tutorial that shows all the steps to obtain an IDS file compliant with the guidelines of buildingSMART International.