In this tutorial, you will learn how to run a Pedestrian Wind Comfort simulation on your project site and we will focus on solving a real-world pedestrian wind comfort challenge. We will test different design interventions aimed at reducing wind discomfort. Using Compare Mode we will see exactly how each solution improves conditions for pedestrians.

Pedestrian wind comfort describes how comfortable or uncomfortable wind conditions feel for people at street level. It is based on metrics like wind speed derived from climate data, along with wind frequency and duration of wind events that might cause discomfort, such as strong gusts or continuous breeze.

Understanding pedestrian wind comfort is crucial for designing safe and pleasant urban spaces. Here is why it matters:

-Urban planning at early stages: Spot potential wind discomfort zones early in the design process to ensure safer streets and pedestrian pathways.

-Designing public spaces and courtyards: Support decisions on how to arrange public areas, orient streets and place vegetation to enhance comfort and usability.

-Evaluating urban microclimates: Assess design options not only for aesthetics but also for their performance under real microclimatic conditions, promoting healthier and more sustainable cities.

We already know how to start a project. If you are new to the process, you can first read running your first simulation guide where we cover how to set up and launch environmental simulations step by step.

Step 1: Choose Your Site and Analysis Type

Start by opening your project in infrared.city. Navigate to the part of the city you want to analyse. In our example, we are focusing on Vienna.

You can analyse the existing city environment, or import your own design geometry to see how proposed buildings or changes might affect pedestrian wind comfort. Simply upload your 3D model to place it on the site before running the simulation.

Click Add Simulation and select Pedestrian Wind Comfort from the list of available simulations. Next, choose your comfort criteria. Each comfort criterion uses different thresholds and methods for evaluating how wind affects people in urban spaces. Available options are Lawson LDDC, Lawson 2001, General Lawson, Davenport, NEN 8100 Safety, NEN 8100 Comfort. The choice of criteria often relates to local standards or regulations used in different countries or regions. You can find further explanation about comfort criteria here.

In this tutorial, we are using the General Lawson comfort criteria, which classify wind speeds into ranges indicating comfort levels for various outdoor activities — such as walking, standing, or sitting.

Once you have selected the analysis type and criteria, you’re ready to define the time periods for your simulation.

STEP 2: Set Up Time Periods for Your Simulation

After selecting your analysis type, it is time to define when you want to run your simulation. In the panel, you will see options for both Season filter and Hour filter.

You can run the simulation using the all year and all hours settings. This produces an overall picture of wind conditions averaged across the entire year, helping you to understand general wind exposure on your site. This is useful in early-stage planning, when you need a broad overview instead of focusing on specific seasonal conditions.

You can also refine your analysis for specific seasons and times of the day. Selecting specific combinations of seasons and hours can give you targeted insights that help shape design decisions for public spaces, street layouts and building orientations. Wind comfort varies throughout the year, and urban spaces often have different uses depending on the season.

For example:

-Spring and Autumn afternoons: Useful for testing conditions for outdoor dining, since people are more likely to sit outside during mild weather.

-Winter mornings: Useful for understanding comfort for commuters or early pedestrian activity in colder months.

-Summer evenings: Helpful to check conditions for outdoor events or night-time urban life.

When you hover over each icon in the hour filter, the exact time range appears so you can easily check which hours you are selecting. You will see icons representing four different time slots:

• 6:00 to 10:00 (early morning)
• 10:00 to 14:00 (late morning to early afternoon)
• 14:00 to 18:00 (afternoon)
• 18:00 to 22:00 (evening)

Simply click on the time slot and season you want to simulate before proceeding to run the analysis.

STEP 3: Run the Simulation

Once you have selected your season and time period, you will see your analysis listed under the Results section. Each analysis card shows the simulation type, the chosen criteria (like Lawson), the season, and the specific hours you have set.

If you have set up multiple time slots, you will see several entries listed here — one for each period you defined.

When you are ready, simply click Run all simulations or run them one by one using the play buttons on each card. When it is done, your results will appear as a coloured map over your project area, showing wind comfort levels according to the criteria you selected.

STEP 4: From Problem to Evaluate Design Solutions

This case study explores how different building geometries influence Pedestrian Wind Comfort in an urban development scenario. A series of massing studies have been developed for a new complex, testing variations in shapes, edges, and building footprints.

The primary objective is to create a comfortable outdoor space between two towers, envisioned as a plaza where people can gather, enjoy food and drinks, and spend time outdoors. To reflect realistic use, the analysis focuses on spring afternoons, a period when outdoor areas are likely to be active and comfortably occupied.

The process begins with Scenario 1, which features simple tower forms with sharp, orthogonal edges. This baseline helps reveal how unmodified, blocky geometries affect wind flow and pedestrian comfort in the surrounding public realm.

In subsequent scenarios, various design changes have been tested, including rotating the towers, adjusting the distance between them, modifying the height of the tower bases, shifting the placement of towers on their podiums, and exploring both closely grouped and separated tower arrangements. Design modifications across scenarios are as follows:

• Scenario 3: The height of the podiums is reduced, and the front facades are tilted. To maintain the same area for the project, the tower heights are increased accordingly. The two towers are slightly separated within the project plot.
• Scenario 5: A different layout is tested by rotating the towers within the plot area.

These progressive adjustments allow for direct comparison of their impact on wind conditions and help identify strategies for achieving more comfortable urban spaces that support vibrant outdoor activities.

To compare the different design scenarios, the analysis was set up using a combination of infrared city and the infrared.city Grasshopper plugin. The project was first created in infrared.city, where the overall context and simulation parameters such as season and desired hours were defined. If you haven’t used the plugin before, you can start learning here.

In Grasshopper, each tower design variation was modeled on a separate layer. A Geometry Pipeline component was used for each layer, allowing the geometries for each scenario to be automatically referenced into the Grasshopper definition. This workflow made it easy to switch between different massing options and run consistent simulations for each design iteration.

The simulations were run for Pedestrian Wind Comfort in a spring afternoon scenario, focusing on wind behavior around the proposed towers and the central plaza area. This process provided comparable results for evaluating how each design adjustment impacted wind comfort levels in the public spaces.

After simulating each scenario, snapshots were created using the Create Snapshot component. This step is crucial for saving each result with a unique name or ID, making it possible to compare scenarios side by side in the infrared.city web application. These snapshots store both the spatial results and KPI data, ensuring that all outcomes can be reviewed and communicated effectively.

If we go to the web app, open the same project, and click on Snapshots from the left toolbar, we can compare key performance indicators (KPIs) across scenarios. That’s why we created the visual snapshots at the beginning - to link each design iteration with its wind comfort performance.

Extended Use Area

Displays the proportion of urban space meeting low wind speed thresholds (≈1.5–2.0 m/s) with minimal exceedance probability, ensuring suitability for prolonged stationary activities.

• Scenario 3 performs best, with 58.12% of the site qualifying as leisure area. The combination of slightly separated towers and tilted facades likely helps break up concentrated wind flows and create calmer zones suitable for long-duration activities like sitting or socializing.
• Scenario 1 follows with 52.66%, indicating that even the unmodified blocky forms offer a reasonable share of calm areas - though these are likely limited to wind-sheltered corners.
• Scenario 5 achieves the lowest leisure score at 30.57%, suggesting that while the rotated layout helps in other aspects, it may create localized turbulence or narrow corridors that reduce the extent of wind-acceptable leisure space.

Transient Use Area

Displays the proportion of space within moderate wind speed thresholds (≈3.0–5.0 m/s) and acceptable exceedance probability, supporting pedestrian mobility and general activities.

• Scenario 3 again leads with 65.27% of the site maintaining acceptable wind comfort levels. The design appears to offer a balanced configuration where the combination of tower height increase, podium tilting, and slight separation reduces wind acceleration near pedestrian areas.
• Scenario 1 closely follows at 63.21%, indicating that even without design modifications, the orthogonal towers provide a decent level of comfort - likely due to their mass blocking direct wind in certain directions.
• Scenario 5 performs worst at 49.99%, implying that the rotated tower configuration, while beneficial in some contexts, may introduce uneven wind flows or channeling effects that limit widespread comfort across the site.

Pedestrian Safety Area

Displays the proportion of space remaining below high-risk wind speed thresholds (>15 m/s) with extremely low exceedance probability, mitigating wind-related safety hazards. All three scenarios - Scenario 1, Scenario 3, and Scenario 5 - achieve a score of 100%, meaning that no parts of the site exceed the wind safety threshold. This indicates that while comfort and leisure conditions vary across designs, all layouts effectively avoid hazardous wind conditions that could pose physical risk to pedestrians.

You can find further information about these KPIs in our Key Performance Indicators knowledge base post here.

Key Takeaway

Scenario 3 emerges as the most balanced design, offering the best overall performance in both comfort and leisure metrics without compromising safety. While Scenario 1 delivers decent baseline results, Scenario 5 falls short in creating usable and comfortable outdoor areas despite maintaining wind safety. All scenarios successfully avoid hazardous wind conditions.