9

Streak Lens Effect 253
channel (page 2–1443) assigned to it. Assign t he
Material ID channel in the Material Editor, using
the Material ID channel flyout (page 2–1444).
The Lens Effect will be applied only to areas of
the geometry where that p articular ID channel is
present.
Tip: Insomecasesyoumightwanttoapplydifferent
Lens Effects sett ings to different pieces of geometry
or IDs. To accomplish this, add additional Lens
Effects entries to the Lens Effects Parameters list.
Then set each different Lens Effect entry to affect a
different Material ID or Object ID and proceed.
Unclamp—An unclamped color is brig hter than
pure white (255,255,255). The software keeps
track of these "hot" areas which tend to show
up when your scene contains bright metallic
highlights or explosions. This spinner lets you
determinethelowestpixelvaluethattheLens
Effect is applied to. Pure white has a pixel value of
1. When this spinner is set to 1, any pixels with
a value above 255 will be glowed. You can invert
this value by clicking the I button to the right of
the spinner.
Sur f Norm—Applies the Lens Effect to part of
an object, based on the angle of the surface
normal to the camer a. A value of 0 is coplanar, or
parallel to the screen. A value of 90 is normal, or
perp endicular to the screen. If you set Surf Norm
to 45, only surfaces with normal angles greater
than 45 degrees will be glowed. You can invert this
value by clicking the I button to the right of the
spinner.
Whole—Applies the Lens Effect to the w hole scene,
notjustaparticularpieceofgeometry.This,in
effect, makes each pixel in the scene a potential
Lens Eff ect source. The areas of the scene that have
the Lens Effect applied to them are determined by
thesettingsintheImageFiltersgroupbox.
Alpha—Applies the Lens Effect to the alpha
channel of an image. The transparency of an alpha
channel is interpreted opposite that of the Mask
channel. Range=0 to 255.
ZHi/ZLo—Highlights objects based on their
distance (Z-Buffer distance) from the camera. The
HivalueisthemaximumdistanceandtheLovalue
is the minimum. Any objects between these two
Z-Buffer distances will be highlighted.
Image Filters group
Filters the Image Sources selec tions to let you
control how the Lens Effect is applied. For
example, you can have ten spheres in your scene,
each with the same Object ID, but different colors.
If you set the Image Source as the Object ID of the
spheres, which selects al l of the spheres, these will
be the only objects in the scene that Lens Effects
will apply an effect to.
However, now that Lens Effects knows where the
pixels are tha t effects can be applied, it needs to
know which ones to actually apply the effect to.
LensEffectsusesthefiltercontrolstofindout
whichsourcepixelstoapplytheeffectto.
All—Selects all source pixels in the scene and
applies the Lens Effect to them.
Edge—Selectsallsourcepixelsalongaboundary
edge and applies the Lens Effect to them. Applying
a Lens Effect a long the edges of objects produces
asofthalothatexistsonbothinsideandoutside
edges of your object.
Per im(et er ) A lph a—Applies the Lens Effect only
to the perimeter of an object based on its a lpha
channel. Selecting this option applies the effect
only on the outside of an object without an y
spill on the interior. Whereas filtering by Edge
produces a spill onto the object, Perimeter Alpha
keeps all of the edges clean because it relies on the
scene alpha channel to derive its effect.
Per im(et er )—Applies the Lens Effect only to the
perimeter of an object based on E dge interference.
Although not as precise as Perimeter Alpha, you