8

Lighting Data Exporter Utility 299
(page 2–1165) , the Physical Scale value is
disregarded, and you don’t need to change it.
•Ifyouuse
Standard lights (page 2–1142) ,the
Physical Scale value acts as a conversion scale
that the radiosity engine uses to calculate
energy. Set it to the equivalent of the brightest
light source in the scene. This will set the
appro priate conversion scale for reflections,
self-illumination, and all other non-physically
based elements a 3ds Max material offers.
However, if you use the Affect Indirect Only
flag in the
Logarithmic Exposure Control (page
3–293)
, you don’t need to worry about the
physical scale setting.
Spectrum bar—Shows the spectrum-to-intensity
mapping. The numbers below the spectrum range
from the Minimum to the Maximum settings.
When rendering with pseudo color, the spectrum
bar is displayed beneath the pseudo color image,
labeled either Luminance or Illuminance.
Lighting Data Expor ter Utility
Utilities panel > Utilities rollout > Lighting Data Export
The Lighting Data Exporter renders the act ive
viewport to images that include
luminance (page
3–1058)
and illuminance (page 3–1049) data that
can be used for lighting analysis.
The Lighting Data Exporter does not render the
files unless you have applied an
exposure control
(page 3–289)
to the scene.
You can render to either the
TIFF file (page
3–684)
format. If you export to a TIFF file, the
utility renders a si ngle im age file that has separate
channels for luminance and illuminance (the file is
of the 32-bit SGI LogLUV image type).
You can also render to the
PIC file (page 3–677)
format. If you export to a PIC file, the utility
renders two images: one con taining l uminance
data, and the other cont aining i lluminance data
(see the description of the File Name button,
below).
Interfa ce
File Name—Click the button to specif y a file name
for the rendering.
When you export to the PIC format, the Lighting
Data Exporter renders two files. It appends the
string “_Illuminance” to the name of one file, and
“_Luminance” to the other. For example, if you
type house asthefilename,theexporterrendersto
house_illuminance.pic and house_luminance.pic .
ImageSizegroup
Width—Sets the output width, in pixels.
Default=640.
Height—Sets the output height, in pixels.
Default=480.
Expor t—Click to render luminance and
illuminance data.
Wa rn in g: Unlike the renderer, if you c lic k Expor t more
than once, this overwrites previously rendered files.