9

Photometric Lights 1301
Ty pe—
Changes t he shape of the area light. Can be
either Rectangle, for a rect angu lar area, or Disc,
for a circular area. Default=Rectangle.
Radius—Available only when Disc is the active
type of area light. Sets the radius of the circular
light area, in 3ds Max units. Default=20.0.
Height and Width—Available only when Rectangle
istheactivetypeofarealight.Settheheightand
width of the rectangular light area, in 3ds Max
units. Default= 20.0 for both Height and Width.
Whileyouusethesespinnerstoadjustthesizeof
the area lig ht, a gizmo (yellow by default) appears
in v iewport s to show the adjusted size. This gizmo
disappears once you finish adjusting the value.
Samples group
UandV—Adjust the qualit y of shadows cast by
the area light. T hese values specify how many
samples to t ake within the light’s area. Higher
values can improve rendering quality at a cost of
rendering time. 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 a long
the radius, and V specifies the number of angular
subdivisions. Default=5 for both U and V.
P hotometr i c L ights
Photometric lights use photometric (page 3–993)
(lightenergy)valuesthatenableyoutomore
accurately define lights as they would be in the
real world. You can create lig hts w ith various
distribution and color characteristics, or import
specific photometric files available from lighting
manufacturers.
Note: Photometric lights always attenuate using an
inverse-square falloff, and rely on your scene using
realistic units.
3dsMaxincludesthefollowingtypesof
photometric ligh t objects:
Target Point Light (Photometric) (page 2–1303)
Free Point Light (Photometric) (page 2–1304)
Target Linear Light (Photometric) (page 2–1305)
Free Linear Light (Photometric) (page 2–1307)
Target Area Light (Photometric) (page 2–1307)
Free Area Light (Photometric) (page 2–1309)
IES Sun Light (Photometric) (page 2–1309)
IES Sky Light (Photometric) (page 2–1312)
mr Sky (page 2–1318)
mr Sun (page 2–1319)
Note: The remainder of this topic discusses
photometric lights with the exception of mr Sky
and mr Sun. For information about these light
types, see mental ray Sun & Sky (page 2–1313).
Distr i bution Capa bili ties of P hotometri c
Lights
Each type of photometric light supports two or
three different light d istribution options.
The point light sources (target and free) support
these distributions:
• Isotropic (page 2–1323)
• Spotlight (page 2–1324)
• Web (page 2–1325)
The linear and area light sources (target and f ree)
supp ort these distributions:
• Diffuse (page 2–1323)
• Web (page 2–1325)