Autodesk 256B1-05A761-1301 - AutoCAD Revit Structure Suite 2010 User Manual page 1230

Parameter
Defining the Initial Intensity
When defining a lighting fixture, you can specify the initial intensity of its light source. The initial intensity
is a measure of how much light is produced by the light source in ideal conditions. (The actual light emitted
by a light source may be reduced by light loss factors. See
You can define the initial intensity of a light source in a lighting fixture family file (as follows). In a project,
you can change the initial intensity of an individual lighting fixture. (See
a Light Source
To define the initial intensity of a lighting fixture family
1 Open the lighting fixture family.
2 Click Family Properties panel
3 For Name, select the family type to modify.
4 Scroll down the list to locate the Initial Intensity parameter, and click in its Value column.
5 In the Initial Intensity dialog, specify values for the parameters.
6 Click OK.
7 Click OK.
8 Save changes to the lighting fixture family.
Initial Intensity Parameters
When defining the Initial Intensity
Parameter
Wattage
Efficacy
Luminous Flux
1188 | Chapter 19 Rendering
on page 1196.)
See Initial Intensity Parameters
The Family Types dialog displays the new Initial Intensity value.
of a light source, define the parameters as follows.
Description
A measurement of the electrical power consumed by a light source.
TIP When adjusting Wattage, it is also important to consider Efficacy. If you change
Wattage alone, you may make the light source unintentionally bright. Luminosity is defined
as Wattage (W) times Efficacy (W/lm). Luminous Efficacy for a 100 W tungsten incandescent
(110 V) is 175, while a 32 W fluorescent tube (T8) is 60.
The amount of light (luminous flux, measured in lumens) produced by a light source as
a ratio of the amount of energy consumed to produce it (measured in watts).
The quantity of light energy per unit of time arriving, leaving, or going through a surface.
The lumen (lm) is the unit of luminous flux in both the International System (SI) of units
and in the American System (AS) of units. If you think of light as particles (photons)
moving through space, then the luminous flux of a light beam arriving at a surface is
proportional to the number of particles hitting the surface during a time interval of 1
second.
Description
which is calculated by multiplying the values of the other parameters. Valid
values are between 0 (total light loss) and 4 (light gain up to 400%). A value
of 1 indicates no light loss (100% of initial light intensity).
Light Loss Factor Parameters
Types.
on page 1188.
on page 1187.)
Changing the Initial Intensity of