9

1582 Chapter 16: Material Editor, Materials, and Maps
Shader Library
Transmat
physics
Transparency
base
Two Sided base
UV Generator (pa ge 2–1724)
3ds Max
Water Surface lume
Wet-Dry Mixer
lume
XY Z Generator (page 2–1729)
3ds Max
Glass Material (mental ray)
Material Editor > Type b utton > M aterial/Map Browser >
Glass (physics_phen)
Note: The Glass material appears in the Browser only if
the mental ray renderer is the currently active renderer.
The Glass material simulates both the surface
properties and the light-transmitting (photon)
properties of glass. It is a mental ray phenomenon
(a scripted shader tree) that is equivalent to a
mental ray m aterial (page 2–1544) with a Dielectric
Material shader (page 2–1719) assig ned to both
its Surface and Photon components, with the
parametersettingsidenticalforboth.Adielectric
material, such as glass, is a m aterial whose surface
transmits most light that st rikes it at angles close
to perpendicu lar (90 degrees), but reflects most
lightthatstrikesatglancingangles(closetozero
degrees).
Note: This material do es not u se a shadow shader,
soshadowswillalwaysbeopaqueunlessyou
generate caustics.
Adjacent Refractive Materials
Two controls, Outside Light Persistence and Index
Of Refrac tion (Out), are for situations where you
are modeling two adjacent refractive materials.
Consider a drink in a martini glass. The glass
has an i ndex of refraction (IOR) of 1.5, while the
alcohol in the glass has an IOR of about 1.3. To
create a physically accurate model of this situation,
use three glass materials: one for the glass itself,
oneforthealcohol,andathirdmaterialforthe
surfaces where they touch each other. For this
third material, set the “inside” IOR to 1.3, and the
outside IOR to 1.5.
Interfa ce
Light Persi stence—In conjunction with the
Persistence Distance, controls the percentage of
lightthatthevolumetransmits. Forexample,if
the color is set to R=G=B=0.5 and the Persistence
Distance is set to 2.0, then objects with a thickness
of 2.0 units w i l l appear 50 per cent transparent.
Default=white (R=G=B=1.0).
Be cause transparency depends on the thickness of
the object, objects with varying thickness show
different transparency depending on the angle
from which they are viewed.
Index Of R efraction—Specifies the Index Of
Refrac tion (IOR). In the physical world, the IOR
results from the relative speeds of light through
thetransparentmaterialandthemediumtheeye
orthecameraisin.Typicallythisisrelatedtothe
object’s density. The higher the IOR, the denser
the object. Default=1.5.
See Extended Parameters Rollout (Standard
Material) (page 2–1471) for a list of IOR values for
commonly encoun tered materials.