9

Highlight Properties 373
inverted by clicking the I button to the right of the
spinner, and can a lso be animated.
ZBufferHiandLo—Highlights objects based
on their distance (Z-Buffer distance) from the
camera. The Hi value is the maximum distance
and t he Lo value is the minimum. Any objects
between these two Z-Buffer distances will be
highlighted. These parameters can b e animated.
Filter group
Filters the Source selections to let you control
how the highlight is applied. For example, you
canhavetenspheresinyourscene,eachwiththe
same Object ID, but different colors. If you set
the Source as the Object ID of the spheres, which
selectsallofthespheres,thatistheonlyplacein
your scene that Highlig ht wil l apply an effect.
However, now that Highlight knows where the
pixels are that can be highlighted, it needs to know
which ones to actually apply the h ighlights to.
Highlight uses the filter controls to find out which
source pixels to apply the highlight to.
All—Selects all source pixels in the scene and
applies a highlight to them.
Edge—Selects all source pixels along a boundary
edge and applies a highli g ht to them. Applying a
highlight a long the edges of objects produces a soft
halo that exists on both inside and outside edges
of your object.
Edge highlights
Per imeter Al pha —Applies a highlight only to the
perimeter of an object based on its alpha channel.
Selectingthisoptionhighlightsonlytheoutside
of an object without any spill on the interior.
Whereas highlighting by Edge produces a spill
onto the object, Perimeter Alpha keeps all of the
edgescleanbecauseitreliesonthescenealpha
channel to derive it’s effect.
Perimeter alpha highlights
Per imeter —Applies highlight effect only to the
perimeter of an object based on Edge inferencing.
Although not as precise as Perimeter Alpha, you
might need to use t he Perimeter option at times
when the alpha channel is unavailable.