On the Projects Dashboard, find your project tile and click “Add Scenario“.
Orbital Stack supports both AI and Rapid CFD within Microclimate simulations. For Cladding simulations, we exclusively utilize our AI engine.
Please select the type of scenario you want to create:
1. Microclimate
1.1 Add a New Scenario
In the pop-up window, choose a name for your scenario and select the Job Level (type of simulation) you would like to run:
- AI Engine
- Rapid CFD
*IMPORTANT: Explore the differences between AI and CFD by reading Choosing Your Simulation Approach – AI vs CFD.
• Select Output Metrics
Under the analysis section, choose Pedestrian Level Wind and select your metrics.
Thermal Comfort analysis is offered as a complementary option and must be specifically chosen as such.
RWDI Abridged: A modified version of RWDI’s Pedestrian Wind Comfort Criteria, simplified to acknowledge the more approximate results generated by AI simulations, or limited wind-direction CFD simulations.
Directional Wind: Directional arrows, or glyphs, are used to visualize the directional flow by positioning 3-dimensional vector arrows at locations across the presentation plane.
Streamlines: Generalized wind flows are shown in color-coded streamlines. This feature is available in all CFD simulations, but exclusively available to monthly subscribers for AI simulations.
Solar Exposure: Identifies where shadows would generally fall for the given season and time or day.
SPMV*: Standard Predicted Mean Vote Modified accounts for the physics associated with elevated solar exposure and humidity ranges present.
- SPMV % Time Acceptable
- SPMV % Time Comfortable
- SPMV* – Hot: Hot and Tropical Climates
UTCI: Universal Thermal Comfort Index quantifies how people perceive given weather conditions by equating them to an equivalent temperature based on standard conditions.
- UTCI % Time No Thermal Stress
Wind Cooling Potential: Provides the average wind speed of a location at an indicated time.
IMPORTANT: To learn more about the metrics available, please visit our knowledge base page.
The next step is a summary of the scenario configuration, and identifies the amount of credits (AI/CFD) this scenario will cost you:
AI simulations:
- Pedestrian Level Wind – 8 AI credits
- Thermal Comfort cost an additional 4 AI credits for 2 seasons or 8 AI credits for 4 seasons. Thermal Comfort must be added as a complementary analysis onto a Pedestrian Level Wind simulation.
CFD simulations:
- Pedestrian Level Wind – 7 CFD credits
- Thermal Comfort cost an additional 3 CFD credits for 2 seasons or 7 CFD credits for 4 seasons
You may choose to purchase the simulation using credits from an active subscription plan or on a Pay-per-Use basis*.
*Note: Pay-Per-Use must to be enabled for your account and for your company. If this option is not available, please contact your company administrator and/or set up an agreement through sales@orbitalstack.com.
When you are finished, click “Create” to begin setting up your simulation.
1.2 Upload and Categorize Geometry
To begin setting up your simulation, upload your geometry files into the corresponding buckets appearing to the left of the screen.
Files must be exported from your CAD software and uploaded in STL file format.
IMPORTANT: Before uploading your Geometry, ensure it has been correctly prepared. Quick tips and detailed instructions can be found on our Preparing Geometry post.
Upload all the required Geometry files by dragging and dropping the files or by clicking the buckets and locating the files directly on your computer. STL Files include:
- Study Building: The main structure of the analysis
- Surrounds/Context: Surrounding structures within 300m of the Study location
- Ground Surface: The terrain around the study building and surrounding area
- Presentation Plane(s): The areas where you would like to see results visualized (ex. street level, rooftops, podia etc). Ensure that you have raised these 1.5 meters above the surface for which you want results visible. You can upload multiple presentation planes, however, our AI engine will combine these into one when viewing the results.
- Overlay: The streets and sidewalks layer for visualization only. Does not influence simulation results, and should be raised 1.7m above grade to be visible over results.
The following are exclusively available for CFD simulations only:
- Landscaping: any large trees or large clusters of shrubs. Please indicate porosity in Scenario Notes Section
- Mitigations: any features that would be installed for mitigation measures (ex. screens, canopies etc.)
As you upload your Geometry files, they will appear in the preview window to the right of the screen.
Within the preview window, click the lightbulb icon at the bottom-left for tips on how to spin and rotate your model to make sure everything aligns as expected.
Once all of your geometry files are uploaded, proceed to the next step by navigating to the bottom right of the page and clicking “Next“.
• Review Geometry Integrity
Before finalizing your simulation parameters, we strongly recommend checking your files to confirm that they are formatted properly in accordance with the considerations which appear on the left of the screen. The viewer will ask you to check off each of these items before moving on to select simulation parameters, though this is not strictly necessary.
You are now prompted to “Run Geometry Validation”
The viewer will warn you of potential issues within your geometry, i.e. surfaces are volumetric when they should be a single flat surface or presentation planes are are not raised high enough. If this happens, you can click the button “Fix Geometry Files” which will take you back to the geometry upload page allowing you to remove your file and reupload a corrected file.
If no issues were found in your geometry files, you can proceed by clicking “Next” in the bottom right of the screen.
IMPORTANT: You can move forward without rectifying your geometry during the validation process. However, it’s crucial to understand that depending on the issue, it may impact your results.
1.3 Select Simulation Parameters
For a Pedestrian Wind Analysis, you will be asked to select the RWDI Abridged and Wind Direction parameters.
If you have requested Thermal Comfort, you will also be asked to select the specific parameters for the metrics you have chosen, i.e. SPMV*, Solar, Wind Cooling Potential, and UTCI.
• RWDI Abridged Parameters
You are now required to set the parameters for your seasons under the RWDI Abridged tab. You may use the default settings, customize them to your preference or copy them from one of the other parameters that have already been selected.
IMPORTANT: Seasons must cover a range of at least 2 months. Time ranges must cover a range of at least 3 hours. Otherwise, an error message will appear near the bottom of the pop-up window.
• Wind Directions & Terrain
You can now navigate to the tab labeled “Wind Directions” to customize your wind parameters.
If you are only simulating a few wind directions, we recommend that you pick the ones that are most common at that site up to a maximum of 8. At any location, conditions are always dominated by the prevailing winds.
To ensure that you have some statistical confidence in the combined Pedestrian Wind Comfort results, it is recommended that there be a minimum of six directions (eight preferred) and that those directions correspond to the most common winds.
If you are unsure of which directions to choose, we recommend that you go with the default eight directions, spread evenly around the compass.
For each wind direction, you are required to select an upwind terrain (aka roughness). If you are unsure of which terrain type to choose, we recommend using a tool such as Google Maps to identify the terrain type adjacent to the site for each direction. For further guidance, check out: Wind Directions and Terrain Considerations (AI)
• SPMV* Parameters
This option will only appear if you have requested the complimentary Thermal Comfort analysis at the scenario creation stage.
The SPMV* Parameters include Seasons, Time of Day, Clothing Profile and Activity.
- Seasons – can be customized, copied from other parameters, or you can choose the default options.
- Time of Day – can be customized or you can choose the default option. For additional guidance, please check out Time Slicing Profiles
- Clothing Profile – choose the clothing type that aligns best with the intended activity of your site. For additional information, check out: Clothing Profiles
- Activity – choose the activity that closest matches the intended use of your space. For additional information, check out: Activity Types
• Solar, Wind Cooling Potential, and UTCI Parameters
These options will only appear if you have requested the complimentary Thermal Comfort analysis and their corresponding metrics at the scenario creation stage.
These Parameters include Seasons and Time of Day. All can be customized, copied from other parameters, or you can choose the default options.
1.4 Submission
Once you are satisfied, click “Submit“.
A pop-up window will appear confirming the total cost of the simulation (in credits). Once you have checked the box to confirm that you have read the Terms and Agreement, click “Submit Scenario“.
After submitting an AI simulation, the page will refresh and results will render within a few minutes*.
After submitting a CFD simulation, you will receive an email confirmation. All results should be available within 2-3 business days*. If we run into any issues, we will contact you directly.
*Note: If there are issues with your submission (i.e. unprepared geometry and/or unaligned Simulation Parameters), results may take additional time.
Please do not hesitate to Contact Us with any questions!
2. Cladding
2.1 Add a New Scenario
In the pop-up window, choose a name for your scenario and select AI at the Job Level (type of simulation) you would like to run. Cladding simulations are run exclusively through our AI engine.
Under the analysis section, select Cladding AI
If you do not have access to Cladding-AI please reach out to your Orbital Stack Representative or contact Support@OrbitalStack.com
• Select Output Metrics
Pressure Coefficients are a non-dimensional way of communicating the pressure on a building’s façade.
Worst Case Pressure Coefficients are determined by identifying the lowest minimum pressure coefficient or the highest maximum pressure coefficient among all simulated wind directions at each location on the building.
Worst Case Pressure Estimates are the envelope of the estimated peak positive and negative surface pressures in kPa.
2.2 Upload and Categorize Geometry
Upload your geometry STLs into each specified bucket.
Note, the overlay bucket is optional and a feature exclusively available to subscribers at the organizational level.
For additional info, please reference our Preparing Geometry Cheat Sheet.
• Review Geometry Integrity
Before finalizing your simulation parameters, we strongly recommend checking your files to confirm that they are formatted properly in accordance with the considerations which appear on the left of the screen. The viewer will ask you to check off each of these items before moving on to select simulation parameters, though this is not strictly necessary.
You are now prompted to “Run Geometry Validation”
The viewer will warn you of potential issues within your geometry, i.e. surfaces are volumetric when they should be a single flat surface or presentation planes are are not raised high enough. If this happens, you can click the button “Fix Geometry Files” which will take you back to the geometry upload page allowing you to remove your file and reupload a corrected file.
If no issues were found in your geometry files, you can proceed by clicking “Next” in the bottom right of the screen.
2.3 Select Simulation Parameters
• Worst Case Pressure Estimates
The Worst Case Pressure Estimates are the envelope of the estimated peak positive and negative surface pressures in kPa. Like the Worst Case Pressure Coefficients, this is the lowest minimum or highest maximum pressure coefficient among all simulated wind directions at each location on the building, but factored by the gradient height wind pressure and adjusted by the Internal Pressure (specified or calculated through the Scenario setup parameters). Orbital Stack adds or subtracts the internal pressure value to generate the most extreme pressure.
The gradient height wind pressure used in Cladding AI is based on the mean wind speed at gradient height, 600m above ground. This wind speed is derived from the Design Wind Speed (hourly mean in m/s) and Design Wind Speed Reference Height (in m) specified in the input parameters. See the Simulation Parameters section of this guide for further details.
• Internal Pressure
Internal pressure is used to calculate the net peak pressures on the façade of the building. It is represented as a deviation from atmospheric pressure. Internal pressure can be calculated by Orbital Stack using the Building Roof Height and the Enclosure Classification, or by specifying a value explicitly. Toggle between modes by selecting either Internal Pressure (specified in kPa, usually < 1kPa) or Specify Building Roof Height (specified in meters).
If providing an explicit value for Internal Pressure, it is generally calculated using the governing code for the project. In general, using ASCE will result in the same positive and negative internal pressure (+/- 0.24 kPa or 5 psf for example). At the moment, Orbital Stack only supports a single internal pressure. For codes that may result in distinct values for positive and negative internal pressures (-0.32 kPa, and +0.48 kPa), such as the EuroCode, it is recommended to use the larger of the two values in order to remain conservative.
• Building Enclosure Classification
Enclosure Classification is used to determine how easily outside pressures balance through the building. This value is only used if Orbital Stack calculates the internal pressure. Specify the Enclosure Classification by selecting an option from the drop-down menu.
- Fully Open
- Partially Open
- Fully Enclosed
• Project North Angle (°)
Projects typically have true North align with the positive Y direction. For cladding studies, users may want to specify a ‘project North’ to align wind directions perpendicular to building faces. If this is the case, input the desired Project North Angle relative to the positive Y direction (true north) in degrees and all wind angles will be referenced to project north rather than true north.
• Return Period Calculations
You can specify up to four return periods and Orbital Stack will determine pressure estimates for each. For each return period, you are required to enter four parameters:
- Return Period: Specify the number of years associated with the return period calculation. This is for reference purposes only.
- Design Wind Speed: This is obtained from code tables and represents the expected peak wind speed for the location and return period. Please ensure this value is input in meters per second.
- Design Wind Speed Average Period: By default, Orbital Stack will assume an hourly mean design wind speed. Should you want to input a wind speed of another average period, please choose the appropriate selection between Hourly Mean, 10 Min. Average, or 3 Sec. Gust. The corresponding Durst Factor will automatically populate based on your selection.
- There is also a Custom Durst Factor selection if you need to convert from another type of average period.
- Design Wind Speed Reference Height: This is the height at which the design wind speed data has been determined or measured (in meters). This height is usually 10m.
• Wind Directions & Terrain Considerations
Wind Directions
Choose between eight (8) and sixteen (16) wind directions.
Terrain Types
Selecting terrain types for each direction provides a more fine-tuned analysis representative of the wider site area, beyond the surrounding buildings included in the model. Choosing the appropriate terrain is important because of how wind is influenced by that environment. For each selected wind direction, review the terrain from 300 to 2000 meters upwind of the site and choose the appropriate Terrain Type. For this, we recommend referring to satellite imagery (e.g. via Google Maps). Choose the Terrain Type that is predominant for that wind direction. For example, a mix of suburban but mostly open terrain could be classified as open to yield slightly windier conditions.
- Open Water: Open water.
- Open: Unobstructed and flat areas, ideal for large bodies of water, fields or parking.
- Rural: Slightly obstructed areas, ideal for farmland or scattered low-rise buildings.
- Forest / Suburban: Partially obstructed areas, ideal for wooded areas, parks, and suburban single family (one to two story) residential.
- Urban: Highly obstructed area, ideal for high density cities two to five story buildings with the occasional high rise.
For additional information on each, check out our post on Wind Directions and Terrain Considerations.
2.4 Submission
Once you are satisfied, click “Submit“.
A pop-up window will appear confirming the total cost of the simulation (in credits). Once you have read and checked the box to confirm that you have read the Terms and Agreement, click “Submit Scenario“.
After submitting a cladding simulation, the page will refresh and results will render within a few minutes*.
*Note: If there are issues with your submission (i.e. unprepared geometry and/or unaligned Simulation Parameters), results may take additional time.
Please do not hesitate to Contact Us with any questions!