8

Photometric Lights 1155
Whileyouusethesespinnerstoadjustthesizeof
the area lig ht, a gizmo (yellow by default) appears
in viewports to show the adjusted size. This gizmo
disappears once you finish adjusting the value.
Samples group
UandV—Adjust the quality of shadows cast by
the area light. These values specify how many
samples to take within the light’s area. Higher
values can improve rendering quality at a cost of
rendering t ime. For a rectangular light, U specifies
the number of sampled subdivisions in one local
dimension, and V the number of subdivisions in
the other local dimension.Foracircular(disc)
light, U specifies the number of subdivisions along
the radius, and V specifies the number of angular
subdivisions. Default=5 for both U and V.
P hotometr i c Li ghts
Photometric lights use photometric (page 3–1087)
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accurately define lights as they would be in the
real world. You can create lights with various
distribution and color characteristics, or import
specific photometric files available from lighting
manufacturers.
Note: Photometric lights always attenuate using an
inve rse-square falloff, a nd rely on your scene using
realistic units.
There are eight types of photometric light objects:
Target Point Light (Photometric) (page 2–1157)
Free Point Light (Photometric) (page 2–1158)
Target Linear Light (Photometric) (page 2–1159)
Free Linear Light (Photometric) (page 2–1160)
Target Area Light (Photometric) (page 2–1161)
Free Area Light (Photometric) (page 2–1162)
IES Sun Light (Photometric) (page 2–1163)
IES Sky Lig ht (Photometric) (page 2–1165)
Distr i bution Capa bili ties of P hotometri c
Lights
Each type of photometric light supports two or
three different light distribution options.
The point light sources (target and free) support
these distributions:
•
Isotropic (page 2–1167)
• Spotlight (page 2–1168)
• Web (page 2–1169)
The linear and area light sources (target and free)
supp ort these distributions:
•
Diffuse (page 2–1168)
• Web (page 2–1169)
Para meters for Photometr ic Lights
Most of the photometric light parameters are
common to all photometric light types, and are
described in the following topics:
Intensity/Color/Distribution Rollout (page
2–1197)
Photometric Linear and Area Lights have rollouts
specific to them:
Linear Light Parameters Rollout (page 2–1198)
Area Light Parameters Rollout (page 2–1198)
Area Light Sampling Rollout (page 2–1199)
The remaining photometric light parameters are
shared with standard lights, and are described in
the following topics:
Name and Color Rollout (Lights) (page 2–1127)
General Lighting Parameters (page 2–1175)