8
1274 Chapter 16: Material Editor, Materials, and Maps
4. Open the Material Editor and choose
Utilities menu > Restore Material Editor
Slots.
The Material Editor status before step 2
is restored.
R eflectance and Tra nsmitta nce
Displ ay
Material Editor > Reflec tance and Transmittance fields
(belowthesampleslots)
These fields show the reflectance and transmittance
oftheactivematerial.Boththeaveragevalueand
themaximumvalueareshown.
Note: These fields are not displayed unless you
turn on Display Reflectance & Transmittance
Informationinthe
Advanced Lighting panel (page
3–866)
of the Preferences dialog.
These fields can change according to the current
Show End Result setting (page 2–1290)
.When
Show End Result is off, the reflectance and
transmittance show the properties of the current
element in the material hierarchy, not the
properties of the material overall.
The reflectance and transmittance values of a
mater ial are p articularly important when you
are preparing a
radiosity solution (page 3–50)
to
obtain a physically accurate lighting simulation.
If a material’s reflectance or transmittance va lues
are not what your scene needs, you need to adjust
these va lues.
Note:
Materials and Radiosity
Upper left: Washed-out walls due to hi gh reflectance.
Right: Better radiosity achieved by reducing the HS V Value
(V) of materials in the scene.
To get good radiosity results, keep these points in
mind as you design materials:
• Before you generate a radiosity solution, check
the reflectance value of all materials in the
scene, to make sure it is not too high. The
reflectance of a material determines how much
of the light energy it receives is subsequently
used in the radiosity calculation. Keep this
value wit hin the range of the physical materials
youaresimulating. (Seethetableinthe
description of “Reflectance,” below.)
• Don’t be concerned if a material preview seems
too dark. For example, a white wall with the
maximum recommended reflectance of 80%
appearsgray.Thecolorbalancewillbeadjusted
correctly b y the
exposure control (page 3–289)
in the final rendering.
• Bitmaps used as diff use textures have already
been illuminated by the scanner, digital camera,
or paint program in which you created them.
To bring them into the proper reflectance range,
you might have to dim them by reducing the
RGB Level value in the bitmap’s
Output rollout
(page 2–1430)
.