Measuring objects


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Observer UGR

Kurt Bieri

The glare caused by luminaires can be evaluated using the CIE's Unified Glare Rating (UGR) method. To do this, the glare of the entire lighting system is calculated

for a defined observer position. According to DIN EN 12464-1, different UGR values have to be observed as a function of the difficulty of different visual tasks. To add

a new UGR observer, go to “Insert/Measuring object/UGR“. With the first click on the floor plan or the 3D view, you create a new UGR point. The observer is placed

at a standard height of 1.2 metres and has a vision range angle of +15 and -15 degrees. The new UGR observer is positioned in the scene tree as follows:

UGR observer in the scene tree

The following parameters can be set for the UGR observer:

  • Viewing direction: this determines the viewing direction in degrees, with 0 degrees being north. The direction can also be changed interactively via the Rotate tool.
  • Angle -: this delimits the viewing direction in the negative direction (in the counterclockwise direction).
  • Angle +: this delimits the viewing direction in the positive direction (in the clockwise direction).
  • Increment:  this shows the distance in degrees at which the observer is measured.

Inclination: this shows the inclination of the observer between -90 and +90 degrees. With a positive angle, the observer looks upward, with a negative angle, the observer looks downward.

If a UGR observer is selected, the observer tools appear in the ribbon bar. The observer's field of vision can be checked here with an animation. Further information on the observer tools

may be found in the chapter entitled <link>GR Observer</link>.

After a scene has been calculated, the output for the glare rating can be opened via the output tree under "Calculation results/UGR“. The maximum UGR value is marked on the output.

In addition, the glare in the angle range is depicted as a red line on a diagram. At the top right of the output, the observer's viewing direction is set out. If glare occurs in this area, this will

be marked with a red line.

 Output for a UGR observer