Illuminance rendering vs lighting analysis

[Anonymous]

Hi I'm Lorenzo, a Revit's user,

I'm doing a study about a room's illuminance with Revit 2015. 

First I have run the analysis with the Revit's plug-in "Lighting Analysis" ; then I have done an "Illuminance Rendering" with the rendering cloud, using the same settings.

But I had different results and I'd like to know why.

It maybe possible that they are using different algorithms?

Best Regards

Lorenzo

For all the analysis  I have use these settings:

- the same geographical location

- the same date and hour (18 September, 9 a.m.)

- the same GHI 406 , DNI 596, DHI 84 W/mq

- clear sky

- the same file 

I attach the images with the results

[scheerd · Accepted solution]

Hi Lorenzo.

Likely the reason is that the LAR analysis grid is at 30 inches above the floor, while Rendering shows on existing model surfaces.

We are going to release a new build of LAR this week that will allow you to set the analysis plane height as well.  I just did an analysis with the plane at 1", and the results match a Rendering ortho 3d camera view of the same floor area of the building pretty well.

Also look out for differences in the Analysis Display Style.  We've tried to recreate the style in Revit that Rendering Illuminance uses, but still the transitions between colors are different with the Rendering built-in illuminance scale and the AVF (Analysis Display Style) scale.  Generally the Rendering scale for LAR previews is set to the max Yellow at 1500 lux, Red at 1000 lux, Green at 500 lux and blue at 0.  You can control that scale when doing an Illuminance type Rendering, or set a custom Analysis Display Style in Revit with the colors at the 1/3 max to min positions.

David