A sufficient supply with daylight and an adequate visual connection to the outside are essential requirements both for the well-being and for the motivation of people who reside in buildings. The required lighting levels can be fulfilled by artificial light, daylight, or a combination of both.

The calculation of daylight occurs in DIALux evo using three different sky models, which are described in the CIE 110-1994: 

  •  overcast sky 
  •  average sky 
  •  clear sky 

The daylight quotient, required in some standards,  can only be calculated with a cloudy sky. DIALux evo automatically creates a corresponding light scene when you perform a daylight calculation. Direct sunlight can be calculated only in clear or average sky.

The calculation of the illumination takes place only in the interior and only by daylight relevant windows, which conduct the daylight inside the building. Other building openings are not considered in the calculation of daylight. Windows that are inside the building are not relevant for daylight. In most cases DIALux automatically detects this. If necessary, you can change this setting at the window in the apertures tool.

Outside the building the scene is only enlighted for visualization. Illumination levels are not calculated.

Location and North alignment

You can arrange the location along with the building in the site tool in the construction mode.


You can either select a location directly from the list or enter yourself latitude and longitude. With the action “drawing north arrow” you can change the orientation of your building. Simply draw the arrow in the 2D floor plan of your scenes.

The north arrow drawing function only works in the site. Alternatively, you can enter the northern alignment directly as a degree value.

Calculating with daylight - Creating a daylight scene

To calculate daylight with DIALux evo, create a corresponding light scene. You can find the appropriate tool in the light mode. To create a daylight scene select another sky model as "No daylight" in the light secene tool. In combination with a window in your project, DIALux evo recognizes a daylight scene, what you also see because the "start calculation" button is activated. 


Here you can select the desired CIE sky model, select the date and time, and if necessary, enable the option "Direct sunlight". 

The option of direct sunlight is available only if you have not selected the overcast sky.

It is up to you whether you want to include artificial light in the calculation of daylight. For a pure daylight scene you must remove all lighting groups from the light scene or fade down all the lights to 0% dimming value. You can create any number of lighting scenes with or without artificial light, each differing in the date, time and sky model.

If you need the results in the outputs please do not forget to activate the "generate outputs for this light scene" setting.

Once you create a light scene with daylight, there will be automatically crated another light scene “Light scene for the energy rating”. In this automatically generated light scene, the sky model "overcast" is always selected. This lights scene is required to display a daylight quotient in the output.


The Outputs for daylight scenes do not need special settings. In addition to the light technical results they contains only information about the place, date time, sky and zenith luminance. In the space summary a daylight quotient is always given.