Add Calculations - Unified Glare Rating

The Unified Glare Rating calculations available in AGi32 are calculated in accordance with the CIE document CIE 117-1995 - Discomfort Glare in Interior Lighting. The shielding effect of the observer's eyebrows and forehead are considered in this calculation. The CIE Unified Glare Rating (UGR) calculation predicts discomfort glare in interior applications from electric light sources. Discomfort Glare is defined as glare that causes discomfort without necessarily impairing the vision of the objects. In other words, you can see the object but may experience discomfort looking at it.

UGR calculations are derived by considering the effect of the luminaire and surrounding environment on an observer's eye. The UGR formula is based on three components:


  1. From the Add menu choose Calculations - Unified Glare Rating, or from the Calculations Toolkit select .
  2. Select the room in which to locate the UGR grids.
  3. Specify a unique label up to 32 characters. The default label will be UGR_1. Unless changed, subsequent labels will be UGR_2, UGR_3, etc. If a number is used for the label, subsequent labels will be incremented accordingly.
  4. An optional description may be entered up to 80 characters. Meaningful descriptions that include room information and work plane height will be useful when generating schedules.
  5. Specify the point spacing from left to right and top to bottom. By default, a point spacing of 10 by 10 is used. As the point spacing changes, the text size adjusts automatically. You may override the text size, if desired.
  6. You may center the measurement points within the grid boundary, if desired, by clicking in the selection box adjacent to Center Points Relative to Grid Boundaries.
  7. Specify a Grid location and Orientation direction and/or specify individual observer locations and their respective orientations.

Specify UGR Grids

Specify UGR Observers

  1. UGR Grids are created by placing multiple observer positions in a uniform array, each looking in the same direction.
  2. Choose which grids to include. By default, Grid 1 is selected and visible.
  3. To change the grid elevation, move the cursor into the Z-Coord box and enter a new value.
  4. To change the Viewing Angle, type the desired Orientation Angle or click the Specify button to specify the View angle graphically.
  5. The View Angle is specified graphically with 2 clicks. The first click locates the Observer position (only used for reference purposes). Drag the cursor to orient the observer and left click again.
  6. Continue in this fashion until all the desired grids are specified. Conventionally, observers are placed to evaluate the worst case conditions (often this means looking at the luminaires crosswise and endwise).
  1. Click the Specify New or Specify Additional buttons to locate individual observer positions graphically.
  2. Observer positions may be located anywhere in the interior environment. Conventionally, they are located at the midpoint of the room walls looking perpendicularly into the room.
  3. To change the Observer elevation, move the cursor into the Z-Coord text box and enter a new value or use the up and down arrow keys on the keyboard, before clicking the Observer location. Locate the Observer by clicking the left mouse button.
  4. Orient the Observer by dragging the mouse in the desired direction and left clicking again. Alternately, you may type in the Orientation angle.
  5. Continue in this fashion until all the Observers have been positioned. Right click to confirm your selections and return to the UGR dialog.
  1. Specify the Summary options to calculate.

UGR Options

Default Selections

  • Average Value
  • Max and Min Values

Other available options

  • Number of Points
  1. Select the display options, including precision (decimal places), text color, perimeter lines, point markers and labeling.
  2. If desired, specify Isoline contouring and Highlight Values by clicking on the appropriate buttons.
  3. Click Ok.