If you have a 10-story building, it takes a lot longer to simulate the whole building in Radiance than to just simulate a single floor. We’re able to do multiple things at the same time There is also no correlation in simulation times between other respected sources of inputs. Simulation times for different rendering parameter setsĪs seen here, the same model can take over 100 x longer depending on the Radiance inputs used. Note that there is no standard for what the “right” radiance inputs should be as it is still largely subjective. The chart below shows the variations in simulation time observed for our 10-story commercial office model for a range of different, well-regarded radiance inputs. We then tested those combinations for speed. At Sefaira, we spent a lot of time researching combinations of inputs that provided comparable results to inputs recommended by other respected sources. Like all rendering software, Radiance requires the specification of a wide range of interrelated inputs for simulations to run. Most daylight analysis software, including Sefaira, uses Radiance as the underlying engine (Daysim, which we also use, is an extra layer on top of Radiance). This article summarizes what we presented in straight-forward terms, in order to explain how we can provide good, accurate calculations at a fraction of the speed expected from daylight analysis. However, one downside of doing quick analysis is that we also get asked, “How can Sefaira’s calculations be legitimate if it’s so much faster than other methods?” So we decided to document and present our processes at this year’s IBPSA USA conference (where all the really serious building physics enthusiasts go). This makes it possible to embrace a cyclic workflow of test – > adjust – > use feedback – > test again, which is what designers need.
![daylight software daylight software](http://andrewmarsh.com/software/daylight-old-web/exp_daylight_old.png)
![daylight software daylight software](https://analysinggreendesign.files.wordpress.com/2010/09/example-for-daylight-analysis1.png)
Most models, even quite large ones, can be set up to return results within a minute. One of the things that customers love about Sefaira’s daylight application is the speed of analysis.