Explanation

The percentage TI (threshold increment) determined for this, is used as an evaluation parameter for the physiological glare and is limited by the corresponding standards (e.g. EN 13201).

Glare rating with the TI method.

To calculate the TI value, it is necessary to have a reference measuring surface in order to take the ambient luminance into account.

Adding a new TI Observer

To add a new TI observer, go to " Insert"  >  "Measuring object" >  "TI"

With your first click on the floor plan or the 3D view you select the observer's position. With the second click you specify the observer's viewing direction. The observer is placed at a standard height of 1.5 metres (EN13201 for car drivers) and takes the nearest vertical measuring surface as the reference measuring surface.

The new TI observer is inserted underneath this reference.

Measuring surface in the scene tree

TI observer beneath the reference measuring surface. 

The reference measuring surface can be changed at a subsequent point in time by pulling the TI observer node to a new measuring surface in the scene tree with the drag & drop function.

The following parameters can be set for the TI observer:

• Number of steps and step increment of the observer.
• Masking angle
• Inclination: shows the inclination of the observer's line of sight, with a negative angle, the observer is looking downward. (Default = -1°)
• Observer's age: age of the observer in years.
• Correction factor: this is the factor for adjusting the luminance. (e.g. DB Guidelines 0.1)
• Rho: reflectance of the ground beneath the observer in percent.

Please note that i f the reflectance of the ground is adjusted, this value must also be changed accordingly.
For more precise information, the corresponding guidelines must be consulted, e.g. EN13201 or the DB guidelines!

If a TI observer is selected, the observer tools appear in the ribbon bar. The observer's field of vision can be checked here with an animation. To do this, you should open the  3D view  (F3 key) and click on the " Start"  button. The different viewing angles will now be shown successively in the 3D view. The speed of the animation can be changed using the controller in the ribbon bar.

If the TI observer is to be positioned according to the DB guidelines, the " DB Guidelines"  button can be clicked.

Observer tools.

TI Observer output (calculation results / glare rating)

After calculating the scene, the output for the TI value can be opened via the output tree under " Calculation results" > "Glare rating" .

The maximum TI value is also documented on the results overview of the reference measuring surface.