Autodesk Forma is quickly growing as an analysis platform that works with native and external (e.g. Revit, Rhino, SketchUp) geometry. The data derived from Forma can be acted upon to make meaningful changes to the design, resulting in improved occupant comfort and building performance. However, as the saying goes, garbage in, garbage out. We need to make sure the correct data is assigned to the adjacent streets (and railways) in order to obtain accurate results.
The two main data points required for road Noise analysis are traffic speed and average daily traffic (ADT).
Traffic Speed Limit
As everyone likely already knows, the speed of traffic has a direct correlation to traffic noise. The imported existing streets sometimes have the speed but not the ADT. Here is how you can find both for a given project location in the US.
OpenStreetMap often has the posted speed limit, as shown in the following image.
- OpenStreetMap: https://www.openstreetmap.org/
If the speed limit is not listed there, and you do not have quick access to the site, try using something like Google Street View to find a speed limit sign. An example is shown in the following image.
Average Daily Traffic (ADT)
The amount of traffic on a street also impacts the amount of noise generated. This data can often be acquired for a State’s DOT website, as shown in the following image.
- Texas DOT traffic data example: https://www.arcgis.com/apps/webappviewer/index.html?id=06fea0307dda42c1976194bf5a98b3a1
We don’t often adjust the daily traffic distribution unless it is for a residential area or we have some other data to justify it.
Rapid Noise Analysis
When the Noise analysis tab is first opened, Forma does a rapid AI-assisted analysis. The location of the circle can be adjusted (notice the custom circle selection).
“Our rapid noise analysis updates in real-time to predict noise conditions based on thousands of simulations. The detailed noise analysis provides a more accurate calculation but takes longer to complete.”
Notice that the rapid results can be narrowed down to roads or rail if applicable. The legend also breaks down the overall decibel levels.
Detailed Noise Analysis
The detailed analysis is crunching the numbers more formally and can take up to 20 minutes for this example. The results are more accurate than the quick, rapid results.
“The detailed noise analysis is in beta which means it is still under development and accuracy of results might be affected. If you notice inaccuracies or inconsistencies, please let us know - this information will be very helpful for us to improve the model”
Notice how the visibility of the projected results can be toggled on/off for the vertical and horizontal surfaces if needed.
Noise Analysis Results
We can use the Inspect tool to tag surfaces within the analysis view to see specific decibel numbers. See the link below to comparative noise levels to better understand the impact. With the data, you might decide to move an outdoor dining area or try adding a break wall or earth berm to see if the impact can be reduced.
- Comparative noise levels: https://www.iacacoustics.com/blog-full/comparative-examples-of-noise-levels
Conclusion
It is clear how easy and accessible Forma can be for a design team at any stage in the project’s development. Below are two Forma links for additional information on this topic.
- Detailed Noise Analysis (Beta): https://intercom.help/spacemaker/en/articles/7793576-detailed-noise-analysis-beta
- The technology behind the noise analysis: https://intercom.help/spacemaker/en/articles/7833234-the-technology-behind-the-noise-analysis
See more about the features and workflows in Autodesk Forma in my YouTube series, sponsored by Autodesk.
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