8

Refraction Mapping 1351
in. Typically this is related to the object’s density.
The higher the IOR, the denser the object.
You can also use a map to control the index of
refraction. IOR maps always interpolate between
1.0 (the IOR of air) and the setting in the IOR
parameter. For example, if you set the IOR to 3.55
and use a black-and-white Noise map to control
IOR, the IORs rendered on the object will be set to
values between 1.0 and 3.55; the object w i l l appear
denser than air. If, on the other hand, you set the
IOR to 0.5, then t he same m ap values will render
between 0.5 and 1.0: as if the camera is under
water and the object is less dense than the water.
HerearesomemoreIORvaluesforvarious
mater ials:
Material IOR Value
Carbon Dioxide, Liquid
1.200
Ice
1.309
Acetone
1.360
Ethyl Alcohol
1.360
Sugar Solut ion 30%
1.380
Alcohol
1.329
Flourite
1.434
Quartz, Fused
1.460
Calspar2
1.486
Sugar Solut ion 80%
1.490
Glass
1.500
Glass, Zinc Crown
1.517
Glass, Crown
1.520
Sodium Chloride
1.530
Sodium Chloride (Salt) 1
1.544
Polystyrene
1.550
Quartz 2
1.553
Emerald
1.570
Glass, Light Flint
1.575
Lapis Lazuli
1.610
Material IOR Value
Topaz
1.610
Carbon Bisulfide
1.630
Quartz 1
1.644
Sodium Chloride (Salt) 2
1.644
Glass, Heavy Flint
1.650
Methylene Iodide
1.740
Ruby
1.770
Sapphire
1.770
Glass, Heaviest Flint
1.890
Crystal
2.000
Diamond
2.417
Chromium Oxide
2.705
Copper Oxide
2.705
Amorphous S elenium
2.920
Iodine Crystal
3.340
Tip: The Reflect/Refract (page 2–1509) map
typeusedasaRefractionmapdoesn’teffectively
model a material surrounding an object, such as a
pencil in a glass of water. For this effect, use either
the
Thin Wall Refraction (page 2–1513) or the
Raytrace map type (page 2–1508) .
Procedures
To create an automatic r efraction:
1.
IntheMapsrollout,clicktheMapbutton
labeled Refraction.
2. In the Material/Map Browser (page 2–1291) ,
choose the
Reflect/Refract (page 2–1509) map
type, and then click OK.
AtaRefractionAmountof100percent,the
material is extremely refractive, regardless of
the material’s Opacity setting. At a Refraction
Amount of 0 percent, the map is turned off.
When the Amount is less tha n 100 percent,
both the Reflect/Refract map and the Opacity
setting control transparency.