Revit Daylighting Tools 1: Autodesk’s Lighting Analysis Extension

One of the most popular posts on this site is “DIVA is Awesome and Everyone Should Use it.” Since that post, Diva has become our staple daylighting tool, but not everyone in our office is familiar with Rhino or more importantly the Rhino/Grasshopper workflow. At LMN, Revit is our production platform and everyone in the office is at least competent in the platform so we were interested in testing a new batch of daylighting tools against our Diva workflow to see just how easily adopted and efficacious they are. In the upcoming posts we will look at the Autodesk Lighting Analysis Extension, Elum Tools new daylighting tool, and Sefiara’s new Revit Add-In with real-time daylighting analysis. The first tool we’ll assess R-Light Small buttonsis the Lighting Analysis Extension recently released by Autodesk. It is a free download and is still a technology preview. The focus of this tool is very narrow. It generates illuminance values in a false color overlay focused primarily on LEED IEQc8.1 2009 or LEED v4 EQc 7 Option 2. The rendering is done through the Autodesk 360 Cloud Rendering service. If you keep the analysis under 25,000 SF it is a free service. If the analysis is larger than 25,000 SF you will be charged 1 cloud “credit” for each additional 12,500 SF.
There is a little set up involved as there is with any daylighting tool. You need to do the basics as far as building orientation and location. Then, you need to ensure that your materials and glazing are set to realistic surface reflectance and Visible Light Transmittance based on their RGB values. Finally, you need to have rooms and room tags and the phase filter needs to be set to “Show Complete.” The tool gives you this little reminder when it starts:
R-Light Instructions

The amount of variables is very small. You may choose either LEED IEQc8.1 2009 or LEED v4 EQc 7 Option 2, High or Low quality (High analyzes a 1’x1’ grid and Low a 6’x6’), and the Levels to be included in the run:
R-Light Options
Typically you will want to run each level alone unless it’s a very small building. The results seem quite accurate and are returned within a few minutes during which time you can continue to work on the model:
R-Light Results

A comparable run in Diva returned almost identical results. That being said this is a one dimensional look at daylighting, based purely on a given point in time for a very specific set of criteria. The cloud based service is great in that it allows you to work locally while it is analyzing elsewhere but it limits the ability to send multiple iterations of specific parameters like head height or glazing material. There is currently no workflow that involves Revit’s visual scripting platform, Dynamo, but Autodesk is working on it by utilizing a brute force approach that utilizes their cloud rendering service (still it only provides illuminance and point in time). The Dynamo workflow, though promising, is more complicated than the Rhino/Grasshopper workflow we are currently using. Without Dynamo there is a lot of manual manipulation and waiting and as a result optimization is greatly inhibited. Finally, there is the issue of credits which, if managed correctly, can be fine but if your model is not setup to analyze under 25,000 SF at a time it can be pretty costly.
So the Autodesk Lighting Analysis Extension is very specific in its goals and very time intensive in its implementation. That said, almost any user in our office could pick it up and get some decent daylighting results as they relate to point in time illuminance values and LEED daylighting requirements. It’s a very nice first step in what we hope will become a more robust tool in the future. In our next post will look at Elum Tools and its new daylighting capability.

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