BIM - Interpretation of IFC elements into building structure elements of InstalSystem 5 package

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Product InstalSystem 5
Type of article FUNCTION AND TOOL
Source for translation 2022-04-22


The InstalSystem 5 package is provided with a number of functions and tools that enable interpreting selected structural components of an IFC model (i.e.: ifcBeam, ifcBuildingElementProxy, ifcColumn, ifcCurtainWall, ifcDoor, ifcFooting, ifcOpeningElement, ifcRoof, ifcSlab, ifcWall, ifcWindow, ifcPlate etc.) into native structural components of InstalSystem 5, i.e.: Wall (including Opening in wall), Curtain Wall, Window (including Roof window), Door, Roof, Slab (including Opening in slab). The interpreted structural components can then be used when working on Thermal calculations of building or when selecting Dokonuj obliczeń świadectw CE, and then also to design a system of any kind.
Functions that interpret the components sort them according to the structure type:

  • Creates walls from an IFC file - Creates structural walls after selecting objects representing walls from IFC file
  • Creates windows, doors, and wall openings from an IFC file - Creates windows, doors and openings in wall after selecting appropriate objects from IFC file (earlier interpretation of walls required)
  • Creates roofs from an IFC file - Creates roofs with edges after selecting appropriate objects from IFC file
  • Creates slabs from an IFC file - Creates slabs with openings after selecting appropriate objects from IFC file.

In addition, when performing interpretation, the user is supported by standard tools to assist in the design process based on the IFC model in the InstalSystem 5 package, i.e.:

  • Search window
  • Project browser window
  • Data table window
  • 2D editor and 3D view windows.

How to use these tools and how to navigate an IFC model is described in detail in: BIM - Import and management of IFC models in InstalSystem 5 package.
Prior to interpreting the building structure into InstalSystem 5 structural components, storeys must be created based on the IFC model.
For more information, see: BIM - Creating storeys based on data from IFC model.

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Location in program

  • Icons of operations allowing to interpretate IFC elements as InstalSystem 5 structural components are located in the 2D editor window ad in the 3D view window in the Main tools toolbar in the Underlay section for the active Underlay. Each function has its own icon located on the toolbar.
    1. Operations available for interpretation of IFC elements as structural components.

Examples of use

Interpreting structural components of an IFC model - general

Selecting components to be interpreted

  • Before running the interpreting function the components to be interpreted must be selected. This can be done using:
  • Components can be interpreted individually or in groups. For example: selecting a group of ifcWall and selecting Creates walls from an IFC file will create native Wall components from all ifcWall components assigned to the selected group.
    2. Selecting a group of components in the Search window.

  • Components that are unchecked in the Project browser window are not displayed in the 2D editor and 3D view windows and will not be interpreted. This mechanism can be used to hide entire infrastructure (low walls, fences, roads), which includes components that are not required to be interpreted in view of further work on the project or when some components are to be interpreted in subsequent steps, e.g. when structural components are interpreted storey after a storey.

Editing the structure created after interpreting a model

  • After interpreting, native structural components of InstalSystem 5 are created within the Construction scope and exist in parallel (simultaneously) with IFC model components within the Underlay scope. After appropriately setting the visibility mode, e.g. Invisible when inactive or Visible when inactive (only edges), the IFC model view can be displayed beside the view of the native structural components depending on the current design needs.
    3. Setting the visibility modes.

  • Within the Construction scope the components created by interpreting an IFC model can be modified at will: moved, removed, have their data changed in the Data table window.
    Note: IFC model components (within the Underlay scope) cannot be modified/removed. They can be hidden (in the Project browser window), and models can be removed entirely and/or replaced with their new versions. For more information, see: BIM - Import and management of IFC models in InstalSystem 5 package.
  • The structure created from an IFC model can be supplemented with manually inserted components using the tools available for the Construction editing scope. These components have an AUTO function for the currently loaded IFC model design. This enables creation of the building structure to be approached in the most efficient way, adapted to the quality of the imported IFC model:
    • The structure can be fully developed using functions that automate the creation process.
    • The structure can be prepared in a hybrid manner - some components are automatically interpreted using the program's functions, while others are inserted manually.
    • The structure is developed without the use of automation functions and the IFC model loaded into the project is used in the same way as a conventional Underlay DWG/DXF.

Interpretation of walls

  • After executing the Creates walls from an IFC file operation, switch to the Construction editing scope and carefully examine the created layout of components.

  • If necessary, correct the components manually or using the Correction of wall geometry operation. For more information, see: Wall geometry correction.
    Problems, which may appear in the created layout of Wall components, result from the fact, that walls are interpreted with preservation of geometry, position and shape according to the IFC model record, which is not always fully compatible with the methodology of creating a building structure InstalSystem 5. The most common situations where the Correction of wall geometry operation should be used with Correct wall connections enabled include:
    • Intersecting walls - if walls in an IFC model have been defined in such a way that they intersect, performing the operation will batch convert all such connections into connections of components that are correctly handled by Computation of building structure .
    • Tangential walls, connected in parallel by their longer edge with each other - if there are such defined components in the IFC model, the best solution is to exclude tangential walls from the interpretation and manually add them or change the wall thickness. If the tangential walls have not been unchecked before interpretation, executing the operation will turn the tangential walls into a single Wall component with the appropriate thickness.
    • Walls, the elevation Z of which begins or ends less than 5 cm from the elevation of the upper edge of the lower slab or the lower edge of the upper slab - such "unadjusted" walls may cause, at a later stage of design, lack of identification of a Room or an Automatic. As a result of the operation, all the walls whose lower or upper edge is less than 5 cm from the slab will be "pushed" to the slab in order to form a closed space of a room.
    • Walls that are contained in another wall will be removed as a group when the operation is executed. This applies mainly to components that were difficult to hide out of visibility before interpreting them and have been interpreted redundantly.

Interpretation of slabs

The concept of using ifcSlab in many IFC models makes the number of interpreted Slab components too large and complicates further work on the project. The Creates slabs from an IFC file operation should be carried out with the following guidelines in mind:

  • Exclude from interpretation (in the Project browser window) components such as step, curb, architectural detail, that are defined in the IFC model as ifcSlab.
  • When the operation is performed, all openings in the slab from the IFC model are interpreted. In a situation where there are a lot of openings, they can prevent proper identification of components Room Automatic. It is therefore necessary to remove such openings and arrange them according to the real needs of Thermal calculations of building. Another option is to uncheck the checkbox in the Active slab holes field in the Data table of the Slab component and carry out Computation of building structure .
    4. Active slab holes in Slab component.

  • In case the slab in the IFC model has been defined with several layers of ifcSlab components, only one slab layer needs to be selected for interpretation, and after the Creates slabs from an IFC file operation the shape of the Slab component should be adjusted, if necessary, with hotpoints and its data changed in the Data table of the Storey component (fields Lower slab thickness and Upper slab thickness).
    5. Slab thickness settings.

  • The slabs defined in the IFC model as tangent tie beams and proper slabs of the same thickness are interpreted as separate Slab components as a result of the operation. If tangency and the same slab thickness are maintained, the program will at a later stage correctly identify the component. In case the constituents of the ifcSlab component are of different thickness or are not in contact with each other, only one of the components should be selected for interpretation and afterwards its shape and data should be modified.
  • After interpreting the construction components from models in which ifcSlab extends only to the inner edges of the walls, the program correctly identifies the components . However, if there are gaps between ifcWall and ifcSlab, the shape of the Slab component after the interpretation operation must be adjusted to follow the outline of the building.

Interpretation of roofs

  • If in an IFC model Roof is defined as multiple objects of the ifcRoof or ifcSlab type, of the same thickness and tangent to each other, the program will, as a result of the Creates roofs from an IFC file operation, create multiple components of the Roof type.

Interpretation of windows, doors and openings

  • Before performing the Creates windows, doors, and wall openings from an IFC file operation, the interpretation of walls, slabs and roofs from the IFC model and Computation of building structure should be performed first, which should be completed with the correct creation of Room Automatic components. Only after this step should one proceed to the interpretation of the components Window (including Roof window), Door or Opening in wall.

  • If the elevation range of the Wall does not match the elevation of the interpreted ifcWindow / ifcDoor object, manually modify Wall by changing in the Data table window the values of the Shift of the lower edge or Shift of the upper edge fields.
  • Objects of the Roof window type in the IFC model are often saved as ifcBuildingElementProxy. The Creates windows, doors, and wall openings from an IFC file function will replace such an object with the proper component if it is marked appropriately.
    6. Roof window as an ifcBuildingElementProxy object in an IFC model.

Additional information

Tolerance in the interpretation of components from an IFC model

  • The program is protected against incorrect object mappings in the model imported into the project. If the user is aware of the target component that the IFC object symbolises, he/she can still effectively use the automated component interpretation functions.
    For example: selecting an ifcSlab component and executing Creates roofs from an IFC file will create a native Roof component (rather than Slab).