Importing IFC files

Motivation and overview of the feature

The chief goal of the IFC import feature is to make it easier and faster to create an acoustical model from an architectural model.

Our solution can be thought of as follows:

• The IFC importer identifies all the spaces in an IFC model and maps them to IFC space tags where available. It will then prepare them for importing into Treble by making some geometrical simplifications that retain only those geometrical details that are relevant to acousticians.

• Our algorithm will provide watertight spaces in as many cases as possible. The algorithm is however still in active development and at this stage not all the extracted spaces will be watertight and ready for a wave-based simulation.

• All imported spaces can be fetched back into our Sketchup plugin for further modification, for example making the space watertight to run wave-based simulation or proceeding with further simplification.

How do we import IFC files?

The following is a brief explanation of the steps our algorithm goes through when processing an IFC file:

Simplification of the input

One of the main challenges is the sheer number of faces that one can find in the details of e.g. furniture. This detail is however often irrelevant when it comes to sound simulations . You can read more about the relevance of details in our software on our documentation here.

So, in order to bring down the simulation time, we run a simplification algorithm which helps reduce the complexity of the input model.

Identification of spaces

Our wave solver needs a watertight space to run a wave propagation analysis, and it is common that IFC files contain several - if not many - different enclosed spaces wherein simulations can be run.

Our algorithm will identify enclosed spaces for each IFC model and prepare them for import in Treble. If the IFC file originates in Revit it is advised that all the spaces you want to be imported into Treble are tagged with the room tag in Revit (see our guide here).

Expected workflow (in the beta)

At the moment, it is likely that the extracted and simplified spaces have small imperfections that prevent them from being watertight or that some undesired geometrical elements are kept. There can therefore be a need to do some manual work on some spaces before they are ready for a full wave-based sound simulation. Our Sketchup plugin has been designed with this workflow in mind as detailed here .

Note: all imported models can be used to run a geometrical acoustical simulation.

Upload an IFC file to Treble

The uploading of an IFC file to Treble is a two-step process.

First an IFC file is uploaded and all the spaces extracted into the Import model (ifc) window. This window is an overview page for all IFC files you upload to Treble.

Then, after the extraction process is finished, you can browse all the spaces in the model and choose which spaces to import into your Treble project.

Open the upload window

The import of the IFC file is initiated by clicking on the new, blue button Import model (IFC). (Note that this might change in the near future.)

Content of the upload window

Once the upload window is open, you can drag-and-drop (or select) an IFC file into the left part of the screen (area 1), like in the normal import.

The upload window also has a panel on the right-hand side, the area 2 on the screenshot that is accessed by pressing the ‘Recent uploads’ icon. This section of the window will be detailed in the Monitor the imports section below.

Pre-processing the IFC file

Once you selected an IFC file, it will be validated by checking that it contains relevant building elements.

Two types of warning can currently be shown:

No space warning

If your IFC file does not contain IfcSpaces (e.g. if you did not tag any Rooms in Revit), a message will warn that spaces will be detected automatically and they will be unnamed. You can choose to continue or edit your file before uploading it.

Only proxy elements warning

If your IFC file was not created through a BIM modelling tool such as Revit or Archicad, it will miss some important information about its internal relationships and building elements. This can happen for example if the model was exported as an IFC file for example from Sketchup (without applying further classification of the internal building elements).

In this case, a message will be prompted, warning you that only "Proxy" elements are contained in the file. You can still upload the file, but the extracted spaces are likely to be unsuitable for acoustic simulation:

• all elements (including terrain, tree and other irrelevant things) will be imported
• no simplification will occur and it is highly unlikely that the wave solver can be used on the extracted spaces
• no layer name will be available when setting the materials

Upload the IFC file

Once the preprocessing is done and is successful you can upload the IFC file by pressing the Upload button.

Once you initiated the upload of a file, the status of the window changes to Uploading file, and a little toast appears at the top

At this point, you cannot close the window or the import will canceled.

Processing of the IFC file

Once the file has been uploaded, our IFC importer starts to process the file. The status in the window change to Processing file.

At this point, you should also see the file on the right-hand side of the upload window, and it is possible to close the upload window and do other tasks in Treble without canceling the import.

The time to process the whole directly depends on its size and the general complexity of the input. A simple model like a residential complex with four three-storey buildings but not a lot of details in the furnishing might take 10 to 15 minutes, while a more complex building might take a few hours. As previously stated, after the processing of a file has started, you can leave the window by pressing the '-' icon in the upper right corner and do other tasks in Treble.

Monitor the imports

An IFC import can be in four different states:

• In progress: when the space extraction is in progress
  
• Ready for import: when the space extraction completed and the spaces can be imported
  
• Error: when the import failed
  
• Cancelled: when the processing has been aborted on the user side
  

Browse the extracted spaces

Access the list of extracted spaces

Once the extraction process has finished, you can click on the blue Import model (ifc) button to access the IFC overview page.

The right side of the page will automatically update to a new panel on the right. By pressing the arrow highlighted on the image below you will be presented with the list of spaces extracted from the input model. You can then choose which spaces to import into a Treble project as explained further below.

IFC Import window

After pressing the arrow you are now in the importing window. The window can be broken into 6 different parts which we will go through in the next sections.

1. Import location

2. List of spaces

3. Viewport showing the 3D rendering of the model of the space

4. Warnings and errors

5. Layer information

6. Feedback

1: Import location

You can choose here where the spaces are going to be imported:

1. Here you choose in which project the spaces are going to be imported. As a general guideline, we recommend to create one project for one IFC model, and if need be, have several import iterations in the same project: if the spaces are the same, a new iteration of the model will be added to that space, making it easy to compare two iterations.

2. Here you can set a default name that will be applied to all of the models that have been selected for import - for example, Initial import for the first import. Note that you can change the name of the model of a space individually in the space list if you wish (see below).

2: List of spaces

This section contains the list of spaces extracted from the IFC file and gives you control over what spaces are imported, how they are named, and where they are imported.

1. Space name (editable) This is the name of the extracted space, based on the IFC spaces that were included in the detected closed volume. If several IFC spaces were enclosed in one detected volume, the names will be concatenated (e.g. “Kitchen, Living room”).

2. Model name (editable) This is the name of the model to be added into the space: if the space already exists, the model will be added to the existing space. As a reminder, each project contains spaces, which themselves can contain several models - each of them being an iteration in the design process. In the web app, when you are in the space view you will be able to see both models.

3. Use this check mark to select or deselect all the spaces

4. Use this check mark to select or deselect this space for import

5. Use this arrow to show or hide the Description field that you can add to the space.

6. Thumbnail of the model of the space.

Note: The editable fields can be edited by clicking on the text.

Thumbnails types:

• A thumbnail with no warning is deemed optimal for running a sound simulation

  

• An orange warning sign indicates that the model has some potential issues, which are detailed on the right-hand side warning panel.

  

• A purple warning sign indicates that the model of the space is not watertight: the model cannot run a wave simulation as is. It might as well have warnings. Note that it can still run a geometrical acoustical simulation.

  

3: Viewport

This section allows you to observe the model, with few functionalities:

• Left-click and drag: move the camera around the view centre

• Right-click and drag: move the camera and the view centre

• Mouse wheel and drag: zoom in and out

You can control what you see in the viewport from the space list (select a different space to show) or on the right side (hide, show or select layers).

4 to 6: Warnings, Layers and General information

You can find a detailed explanation on the whole right section from our web app import documentation here.

Import the spaces

Once you have provided a destination project and curated the list of space models that you want to import, you can proceed by clicking on the Import selected space (X).

The importing process is then started. It usually takes from few seconds to a couple of minutes to process the whole list.

Important: Once you click this button, you cannot return to this window and import another selection of spaces from this IFC space extraction (this might change in the future).

Inspect the spaces after import

Project view

After importing the extracted spaces, they are all available in the main view, within the chosen project. In our case, we imported the 72 spaces of the input model, so we have a whole list of spaces displayed in the project view below. You can use the search function on the top of the window to search for project or spaces.

You can click on a space to open its view, and see the list of its model iterations.

Space view

In this example, there is only one iteration of the model of the space. The purple circle indicates that the space is not watertight, and that wave simulations will not be available.

You can click on the model to open the information panel on the right, and then click on Open to open its view.

Model view

Here the cause of the non-watertightness of the space is obvious: one large triangle got omitted. One can also see that the other side of the wall is protruding far above the ceiling: these are the sort of artifacts that are expected, and that we are currently focusing on solving.

Below is a comparison between the furniture in the IFC file and the imported geometry: only the acoustically relevant parts of the chairs and the table have been kept, which decreases the simulation's runtime.

Make a non-watertight model watertight

Using SketchUp

If you have a SketchUp license, you can fetch the model that you imported in Treble using our SketchUp plugin:

You can use the regular SketchUp workflow and our Geometry Checking Service to fix the problems and upload a new model of the space, this time watertight:¨

You can see that the upload of the new iteration of the model (Watertight version) is now alongside the original model (Model 1).

Using the downloaded source model

In the space view, you can also choose to download the source model file, which is the model of the space that has been extracted from the IFC file and imported into Treble. You can do so by clicking on the three dots on the right side of the model banner, and select Download source model.

Once you have downloaded the source model, you can open it in the 3D model editor of your choice.

Note: Should your modelling software ask, the unit of the DXF model is meters:

Here is the model opened in Rhino:

Once you have completed the fixing of the model, you can export it as DXF, 3DM or OBJ and import it through the standard import button in the web app Import model:

When importing the model, choose the Project of your IFC file in the field 1 below:

If you click in the name of the space, the list of existing spaces for this projects pops out, and you can select there the space where you pulled the source model from (here, Cafeteria, Service).

You can then edit the name of the model to a name that makes sense for this iteration. In this case, Fixed source model.

Click on Import at the bottom and you are set: this iteration has been added as a model of the space, and can be selected for running simulations in the space.