Frequently Asked Questions

Getting Started and General Information

To get started, schedule a demo with one of our experts to get familiarized with the benefits and functions of the application.

Login by going to and clicking on the Login button in the upper righthand corner. Then enter your username and password. If you do not have an account, Contact Support to book a demo and free account.

You can open a support request by completing and submitting the form here. We will respond to you within 12 business hours.

No, Orbital Stack is cloud-based and requires an internet connection to work.

OS uses CFD that has been tailored to urban flow simulation. The CFD solver has been validated against hundreds of wind tunnel results to provide the most accurate solution possible in an efficient manner

No, you do not need to be an expert, however, it is important to run through a demo with us, so you understand exactly how to use and navigate the program. We also provide step by step instructions in the Getting Started Guide, as well as supplementary information on this site.

Orbital Stack uses meteorological data from RWDI and other high quality sources. The RWDI data is typically measured data that has undergone quality control.

Projects and Simulations

Thermal comfort is finding a perfect balance when people in outdoor spaces aren’t too cold, too warm, and when it’s neither too sunny, too cold, nor too windy for pedestrians. You can find a detailed definition and breakdown in the Study Type Library as well as the Glossary and Color Legends Explained

PMV is used to convey Thermal Comfort by predicting what 80% of people in a large group “felt” on a seven-point thermal sensation scale that measures the deviation between heat loss and metabolic rate. PMV was initially developed to rate thermal comfort conditions inside offices and other types of buildings.

PLW or Pedestrian Wind refers to the engineering analysis of wind relating to the comfort of pedestrians. You can find a detailed definition and breakdown in the Study Type Library as well as the Glossary and Color Legends Explained

The “Standard Predicted Mean Vote Modified” (SPMV*) metric is used as it can effectively account for the physics associated with elevated solar exposure and humidity ranges present outdoors. You can find a detailed definition and breakdown in the Study Type Library as well as the Glossary and Color Legends Explained

The current Study Types we have available are Pedestrian Level Wind, Directional Wind, Thermal Comfort and Sun/Shadow. You can request more than one Study Type per simulation.

You can upload almost any type of above-grade development such as; masterplans, tall buildings, midrise buildings, multiuse complexes, hotel resorts etc.

Currently, no, Orbital Stack is standalone software. You must export your geometry as STL files and then upload them into the software.

Utilize the Project Assets Layer Picker to toggle through the different results for each Study Type. Each layer has a Color Legend that indicates the attributes of the results. For example, the PLW Abridged Comfort Criteria Color Legend will indicate that blue is comfortable for sitting and orange to red is uncomfortable. Check out the Color Legends Explained Guide for more information.

The Color Legends within The Viewer will show you the raw results of where you may see issues such as thermal discomfort or high winds. We also have a comprehensive Study Type Library to help you fully understand and interpret your results. For a quick reference, check out the Color Legends Explained Guide

For a nominal fee, you can “Phone a Friend” at RWDI and schedule a live overview with an RWDI Engineer to get the most out of your results. You can either contact your Orbital Stack Representative directly, or message Contact Support

When a project has been shared with you, you will receive a notification in the Orbital Stack web app. To accept the project share, click on the Bell icon near the top right corner of the screen, then click “Accept”.

For instructions on sharing projects, visit our Share Settings guide.

Typically, results are available 48 hours after submission. For larger more complex Master Planning projects, it could be slightly longer.

Technical Guidance

If your .STL files exceed the size limits (20MB for AI; 50MB for CFD), try reducing the number of meshes in your objects (e.g. Reduce Mesh function in Rhino3D). You may also try reducing the level of detail by eliminating tiny objects that aren’t critical to the simulation.

The total surface area of your prepared geometry (ground and surface area of all buildings including façades) cannot exceed 3km2. If you receive this error, try eliminating some of the surrounding buildings outside of your project limits. We also recommend limiting the ground surface radius to 900 meters or less.

We typically support areas that are wider than 3 meters

You should be able include those balconies.  If there are balustrades, you can model them as thin surfaces or ignore them (the typical 4 feet high balustrades will not impact the wind at shoulder height).  Ideally, any small items should be removed from the model.

You can submit the model as is.  Offsets larger than 2 feet are important for the wind flows.  That being said, you don’t need to remove smaller changes.  Our wrapping process will decimate those features.

This issue occurs when the presentation surfaces are not elevated above the building / ground surfaces for which you want results to appear. Consequently, results will be hidden within the building / ground surfaces and will not display properly. To fix the issue, please ensure that your presentation surfaces are raised by 1.5 meters above the locations for which you want results to appear, in accordance with our Preparing Geometry guide.

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