Autodesk 24000-000000-9860 - Revit Architecture - PC, User Manual

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Defining the Light Loss Factor
The light loss factor is a value used to calculate the amount of light lost due to environmental factors, such
as dust and ambient temperature.
You can define the light loss factor for a lighting fixture family file (as follows). In a project, you can change
the light loss factor of an individual lighting fixture. (See
Changing the Light Loss Factor for a Light Source
on page 1133.)
To define the light loss factor
1 Open the lighting fixture family.
2 On the Design Bar, click Family Types.
3 For Name, select the family type to modify.
4 Scroll down the list to locate the Light Loss Factor parameter, and click in its Value column.
The Light Loss Factor dialog displays.
5 To use a simple calculation for Light Loss Factor, do the following:
a For Method, select Simple.
b For Total Light Loss Factor, move the slider to adjust the value between Dimmer and
Brighter.
c Click OK.
6 To use an advanced calculation for Light Loss Factor, do the following:
a For Method, select Advanced.
b Under Value, adjust the sliders for each parameter, or enter a value in the text box.
See Light Loss Factor Parameters on page 1123.
c Click OK.
The Family Types dialog displays the new Light Loss Factor value.
7 Click OK.
8 Save changes to the lighting fixture family.
Light Loss Factor Parameters
When you turn on a lighting fixture, light travels through the light source (lamp or ballast) and the lighting
fixture (such as a lamp shade or lensed troffer), until it reaches the work plane where it is needed. Along the
way, the amount of transmitted light is reduced, obscured by the light source, the lighting fixture, and other
environmental factors. The Light Loss Factor measures the reduction of light as it travels from the light
source.
When defining the Light Loss Factor for a light, define the parameters as follows. Check with the lamp
manufacturer for the appropriate Light Loss Factor values for a particular type of lamp.
Description Parameter
For fluorescent light sources, a measure of the amount of light lost or gained
due to deviations above or below the ideal operating temperature. Valid Temperature Loss/Gain Factor
values are between 0 and 2. A value of 1.0 indicates that no light is lost or
Creating and Modifying Lighting Fixtures | 1123