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1136 Chapter 15: Lights and Cameras
and u se lig hts that effect ambient only to simulate
theregionalareasofdiffusereflection.
You set the scene’s ambient light using the
EnvironmentAndEffectsdialog>
Environment
panel (page 3–268)
.Yousetalighttoaffectonly
ambient illumination with its
Advanced Effects
rollout (page 2–1185)
>AmbientOnlycheckbox.
Posit ionin g Li ght Obj ects
Once you have placed lights in y our scene, you
can use transforms to change a lig ht’s position or
orientation.
Transforming Lig hts
Usetransformsonlightobjectsasfollows:
Move: Use Move (page 1–419) to change
the position of lights. You can also use it to change
the position of light targets.
Rotate: Use Rotate (page 1–420) to change
the orientation of lights.
Note: You can’t rotate a target light about its local X
orYaxes.Instead,useMovetomovethelightor
its target. Rotating the light about its local Z axis
can be usefu l if t he light uses a rectangu lar beam
or pro jects a bitmap.
Rotating a plain omni light or a photometric
isotropic light has no effect as these lights cast light
uniformly in all directions. However, rotating
an omni or isotropic projector light causes the
projected image to rotate.
Rotating a photometric isotropic light has no effect
as these lig hts cast light uniformly in a ll directions.
However, rotating an isotropic projector light
causes the projected image to rotate.
Scale: Scaling Point, Linear, or Area lights
has no effect. Using
Scale (page 1–421) with
spotlights and directional lights changes the
size of their light beam and attenuation ranges.
Scaling omni lights changes only the attenuation
ranges. Scaling photometric lights changes their
attenuation rate.
Light viewpor ts (page 3–792) are another
convenient way to transform and change
param eters of spotlights and directional lights.
Tip: When you adjust lig hts, it can be useful to turn
on
Degradation Override (page 1–34) .IfOverride
is off and shaded v iewports begin to display in
w ireframe, you can’t see the result of the changes
you make to lights.
Placing Highlights
Yo u u s e Place Highlight (page 1–452) to position a
light to create a specular highlight at a designated
point on an object. Place Highlight is one of the
buttons on the Align flyout. Place Highlight moves
or rotates the selected light object to aim it at a
face on an object you pick. The light maintains its
original distance from the face. Place Highlig ht
works with any kind of selected object. You
can also use Place Highlight with a selection set
that contains more than one object. All objects
maintain their initia l distance f rom the face.
Animating Lights
You animate lights by using transforms or changing
creation par ameters on different key frames while
the
Auto Key button (page 3–760) is on. During
animation, light transforms and parameter values
are interpolated between keyframes.
Moving and R otating Light Objects
You can use the following methods to move and
rotate light objects.