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Import Options and Configuration Settings

Because IFC models may be created with different authoring tools and modelling practices, the same type of building information can be structured in different ways from one file to another. To account for these differences, IDA ICE provides a set of import options that allow the user to control how the IFC model is interpreted when it is loaded into the program. These options influence how geometry, spaces, façade elements, and attributes are brought into the IFC environment of IDA ICE and therefore define the starting point for the next stage of working with the imported model.

Import an IFC

An IFC model can be imported into IDA ICE through several entry points within the interface. The import can be initiated from the main menu, from the Floor Plan tab, or from the 3D View tab. It is also possible to start the process by dragging and dropping an IFC file into the workspace. Each of these actions starts the same import procedure. Once the IFC file is selected, the import dialog appears, allowing the user to review and adjust the configuration settings before the geometry and information from the IFC model are loaded.

Merge Windows

Since the number of windows can significantly impact simulation speed and model responsiveness, IDA ICE provides the option to merge windows during import. When this option is enabled (default), all windows belonging to the same wall are combined into a single window whose total area equals the sum of the individual windows. This simplification reduces the number of geometric objects and improves computational efficiency, especially in large models.

Merging windows introduces a simplified representation of façade elements that is generally well suited for energy simulations. In this approach, all windows within the same wall share common properties such as shading conditions and surface temperature, and thermal bridge effects are treated in a more aggregated way. The position of the merged window represents an overall approximation rather than the exact placement of each individual opening.

This level of simplification is typically appropriate for energy performance analyses, where the overall thermal behavior is more relevant than detailed geometric distribution. For more detailed studies (such as daylighting, CFD, or thermal comfort simulations) the user may need to consider whether a more explicit representation of individual windows is required. In such cases, disabling the option allows each window to be imported separately, preserving the original geometric detail at the expense of increased model complexity.

Use Grosspaces

The Use Grosspaces setting controls how building bodies and storey outlines are derived. Since IFC does not explicitly define building bodies, IDA ICE reconstructs them from available geometry. In some BIM workflows, gross area definitions are exported as IfcSpaces that cover the entire floor and can serve as a reliable representation of the storey shape, particularly when their geometry is simple. When such a gross space exists and the option is enabled, IDA ICE uses it to define the storey boundary, providing a clear and consistent outline if it encloses all other spaces on the same storey. Depending on the Keep Intersecting Spaces setting, this space may also be imported as an IFC space. For best results, gross spaces should be defined along the inside faces of external walls.

If no gross space is available, or if the option is disabled, IDA ICE reconstructs the storey outline from wall geometry. The software first attempts to determine the boundary from walls identified as external and, if necessary, uses all walls in the storey. If this reconstruction is not successful, the building outline may need to be adjusted manually after import.

Ignore Roofs

The Ignore Roofs option controls how roof geometry from the IFC file is treated during import. When the option is not activated (default), IDA ICE attempts to create building bodies that follow the roof geometry as defined in the IFC model. However, roof geometries in BIM models can be highly complex, which may lead to difficulties or even failure during import. In practice, generating meaningful building bodies from complex roof shapes is often challenging.

When the option is enabled, the detailed roof geometry is ignored for the purpose of building body creation and replaced with a simplified planar roof at the top level. This improves the robustness of the import process and provides a clearer starting point for further modelling. Regardless of this setting, the original roof geometry is typically still imported as IFC geometry and remains available as a reference. In cases where more accurate building bodies are required, additional modelling operations (such as extrusion as building body) may be applied to the imported geometry.

Keep Intersecting Spaces

Finally, Keep Intersecting Spaces determines how overlapping spaces from the IFC model are handled. IFC models may contain spaces that overlap because they serve different purposes, such as room definitions, circulation areas, or gross floor areas. By default, overlapping spaces are simplified during import so that only one of the intersecting spaces is retained. When this option is enabled, all spaces are imported, including those that overlap, preserving more of the original data.

These imported spaces act as intermediate objects that can later be used to define thermal zones. Depending on the modelling approach, individual spaces may be converted directly into zones, or multiple spaces may be combined into a single thermal zone.

Space Text Attributes from Slots

The Space Text Attributes from Slots setting controls how naming and structured information for spaces is interpreted during import. In IFC models, space-related data can be stored in different attributes such as ifcName, ifcLongname, and ifcDescription, and the user must decide how these correspond to names, groups, and descriptions in IDA ICE. Often, these attributes are used inconsistently, for example when ifcName contains only numbering while descriptive information is stored elsewhere. The import options allow this information to be combined or reassigned to produce meaningful naming, and the user can review examples from the IFC file and adjust the mapping if needed by reimporting.

Additional IFC options

Additional IFC import options are available in the Floor Plan tab. Open the IFC… menu at the bottom of the window to access them.

Additional IFC options allow you to define how the imported model behaves inside the IDA ICE environment. For example, IFC walls can be enabled to divide newly created zones, which is useful when zones are defined manually or when the IFC file does not include predefined spaces. A threshold value can also be specified to determine when a wall is considered external, helping IDA ICE correctly interpret the building envelope during the import process.

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