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Getting started with CFD

Last modified by Niklas Wikström on 2026/10/26 15:12

About this Getting started guide

This guide is structured like a handbook, with each section representing a step in the workflow for using the IDA ICE CFD extension. It includes an Introduction Exercise that is presented progressively. At the end of each section, some of the methods introduced are incorporated into the exercise. The Introduction Exercise is a simple example designed to walk you through the CFD extension process from start to finish.

If you have not already installed the CFD extension, please visit the CFD installation instructions.

Contents

The Introduction Exercise is divided into separate steps. Each step builds on the previous one, so consider it as one complete exercise, not as separate tasks. Each part of the exercise is described at the end of the first six sections of the guide described below.

Notes

Prerequisites

Enable 64-bit visualization

To visualize CFD results in IDA ICE, the 64-bit Animation tab must be enabled.

  • Options -> Preferences -> General -> Check "Use 64-bit diagram and animation (Beta)
  • Restart IDA ICE

The language should be set to English

The CFD extension is not well tested with language settings other than English. Changing the language while working on a CFD model usually cause errors, since geometry to data mappings may be based on translated strings. Language is configured under IDA ICE main menu > Options > Language.

Visualization issues and workarounds (Animation tab)

Resetting the Animation tab:

  • Delete the Animation (by default there is only one) under Outline → Animations → Animation.
    • Right-click and select Delete.
    • In the error message, choose Abort.
    • In the Animation tab, click the + button to add a new Animation.
  • Alternatively, save your project and restart IDA ICE.

Fixed in IDA ICE 5.2 - Cut plane location bug, in older versions of IDA ICE

Creating a cut (result slice) of CFD results to visualize a variable cause a crash if the specified cut level is outside the CFD domain (i.e., outside the room).

Saving CFD cases

CFD cases are saved, optionally, when saving the building. This process may take a few minutes, since unsaved CFD cases will be reconstructed, compressed and fetched from the backend to the file system. Note that the building model will be saved unpacked if it contains one or more CFD cases. Detailed information about how CFD cases are saved  is found here .

Do not overwrite an existing IDA ICE model

Do not save an IDA ICE file to an already existing file if both models contain CFD data. This may cause a loss of CFD data. Instead, always save the file with a new name, do not replace an existing file. Further information.

Relocating model files (IDM files)

When opening an existing CFD project from a stored location and saving it under a new name in a different location, the user must first open the CFD tab to initiate the automatic update of paths for all CFD cases.

General advice

  • Start out by running very small cases to practice and learn e.g. the effects of mesh size settings and the work flow.
  • If possible, work on your local hard drive, since saving large data to remote storage can be very time-consuming.
  • Keep the IDA ICE model clean and as simple as possible.
  • Do not import too much or detailed CAD geometry, since this will make the CFD simulation less robust and much more time consuming.
  • Run only one CFD session in an IDA ICE session.

Useful links

👉 Full CFD installation instructions.
👉 Please view the known issues page.
👉 More Advanced topics
👉 Here you find CFD Download material

Special actions

Resetting the backend is needed if the size of the backend has grown too big on the disk. It is advised to reset the backend now and then.

👉 But be careful to save any active CFD cases before resetting the backend.
👉 Close IDA ICE and open a new file.
👉 Open CFD tab
👉 Click blue "Manage WSL" -> Click "Reset backend"