Cloud based daylight simulations #2

This is part 1 of the 3 part blog post about cloud rendering. Lightstanza is a simple online tool that works by uploading 3D models made (or imported) from Sketchup. As of now, its functionality is limited to Sketchup, but the team is working actively to develop Rhino and Revit add-ins. This would be helpful as a lot of architectural firms including LMN use Rhino and Revit more than Sketchup. Lightstanza is a great tool since you can upload the model to the online website and let multiple simulations run at the same time. The tool is able to perform  simulations for various daylight metrics (all that are really needed) viz. sDA, ASE, DA, CDA, UDI, Mean Illumination, hourly/point in time illumination, glare based on set views/scenes and false color images. It can also analyze the design for LEED compliance based on sDA and ASE. Cloud computing enables one to keep modelling design variations and in the meantime simulate other options.


For daylight simulation, Lightstanza requires illumination grid to be created in Sketchup using its extension that is installed locally on the machine.

Plug In

Sketchup Plug-in



Checklist in Sketchup before uploading the model

It also requires the model to be geo-located to help the software calculate the surrounding ground reflections, which is great as it improves the accuracy of the simulations. Additionally, interior or exterior views or scenes need to be added as these are used for false color and glare analysis – again a great feature specifically to compare different times of the day and year. Advanced simulation includes adding “Window Assembly” to some or all of windows which essentially refer to adding interior dynamic blinds to the window. The blind operation is controlled by two settings – Solar or sDA specification. This is a great feature as one can compare not only illumination and annual daylight metrics for options with and without blinds, but also compare views for daylight quality or glare. The tool works by detecting the geometry in Sketchup by materials and layers. This can be edited later online and helps to compare different materials, and textures, but also lets you model design variations in one model using different layers and toggle them on and off online.


Once the model is uploaded, some work needs to be done to create variations of the design and set the materials and properties. Since the tool reads the Sketchup materials, it separates all geometry by materials. The materials and properties can be set using the pre-defined values, or custom materials can be created which again is helpful to get more accurate results and/or test different design variations.

Material Selection Online

Material Selection Online


After the material and model setting, the only thing left is to run simulations. This is where Lightstanza stands out because it lets you do multiple simulations at different settings at the same time. Of course, the time for each would be different, but everything runs parallel at the same time. The tool gives the options of setting up a ‘draft’ simulation or a ‘medium’ quality simulation which essentially translates to the accuracy. The grid size for sensor placement can be set from pre-set values ranging from 1′ to 10′. The time for simulation depends on both these settings.


Grid Setup

Simulations Running

Simulations Running


Lightstanza lets you compare different times of the year and hours of days (options of running simulations either at a specific hours, or multiple hours on Solstice and Equinox) in a “Key Times” mode. In the annual mode, the web interface neatly places all metrics in a row for every floor. Another useful feature in Lightstanza is the ability to view false color images and change exposure settings on the views (the scenes that were set in Sketchup). These scenes are photo realistic renderings using Radiance and were comparable to similar studies done on DIVA. Lightstanza can also analyze these scenes for glare (there is an option to simulate using perspective or hemispherical lens). This is really helpful, though as with any glare analysis, setting up the camera can affect the glare probability results. The results for both key times and annual are downloadable in multiple formats. The other great feature of the tool is the ability to simulate blinds for ASE and glare. If the uploaded Sketchup model includes ‘windows assemblies’ set using the Lightstanza toolbar, the web interface can simulate the blinds. There are two settings available for this: Solar Control or ASE Control. The Blind operation can be viewed in the visualization (scene) as well.


Key Times – Point In Time Illuminance


Renderings at different times of the day

Annual Metrics

Annual Metrics

The timing of simulations among others (graphics, ease of setup) is a key important feature in a cloud based rendering software. My simulations took from a couple minutes to about an hour for the analysis of 40 ‘key times’ (shoebox or a big 4 floor building). For annual simulation, these times can be expected to be in the range of couple minutes to about even about an hour or longer (depending on the model complexity, size and grid dimensions). These times are not the best, but they are not bad compared to the existing daylight simulations methods done on local computers. Besides since its not using local machine resources, it works well.

The graphics and visuals are clear and to an extent are customizable. As of now, you can change the appearance of key time metrics with different colors and grid node shapes. The team is working on improving these controls and provide similar options for the annual simulations as well. There are options for downloading the key time hourly simulations as avi animations to see hourly/monthly results. Annual files can also be downloaded in csv format to process data in different ways. Apart from that, customizable vector files, png images are available for download. The activity trackers and simulation history are all neatly stacked and makes the process of tracking design variations simple.

In short, Lightstanza is a great tool for doing daylighting studies once a 3d model has been generated with all elements. Although the tool’s functionality is limited to Sketchup right now, we tested a few models exported from Rhino to Sketchup, and they seemed to work decently except the work that needs to be done to sort out elements by materials (which can be an extensive activity in a big model). The online web interface works really well as it removes the need for a dedicated high performing computer system. The online interface also works really well in collaborating as the results are always available and compiled in a way that they can be directly used for reports and presentations.

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