8

Render to Texture: Projection Options Dialog 161
other current Projection Options settings. This
button is available only when there is an individual
source object.
Filtering Options group
Cr o p Al p ha—Removesantialiasingfromthealpha
channel.
Global Supersampler—When the default sc anline
renderer is active, the text field shows the type
of global supersampling that is currently in use.
When the mental ray renderer is active, it shows
the number of samples per pixel. Default=None.
•
Setup—Click to set up global sampling.
When the default scanline renderer is act ive,
clicking Setup displays the Render dialog’s
Default Scanline Renderer rollout (page 3–37) ,
whose Global Supersampling group lets you
globally enable supersampling, and choose
the supersampling method. When the mental
ray renderer is active, clicking Setup displays
the Render d ialog’s
Sampling Quality rollout
(page 3–97)
, which lets you adjust the level of
sampling.
Method group
Thesecontrolsletyouchoosehowtousenormals
from the source object.
•
Raytrace—( The default.) When chosen,
normals are ray-traced between the source and
target objects. The objects need to be perfectly
aligned in
world space (p age 3–1130) .When
you view both high-res and low-res objects in
viewports, they must line up with each other
exactly. There are no sp ecial requirements
for the mapping coordinates of the high-res
objects.
•
UV M atch—When chosen, normals are obtained
by matching the target object’s local UV
coordinates to those of the source. The objects’
UV coordinates (p age 3–1122) need to be
perfectly alig ned. If you look at the objects
using the Unwrap UVW modifier’s
Edit UVWs
dialog (page 1–878)
,thelow-resandhigh-res
objects must be lined up with each other
exactly. The hig h-res object needs to have
mapping coordinates on the same map channel
you are using for the low-res object.
Typically, the high-res object will have an
Unwrap UVW modifier assigned to it, but this
is not required.
With this option, the high-res object does not
needtobeinthesamephysicallocationasthe
low-res object.
Tip: You can Reset the cage (on the Cage rollout
(page 1–764)
), because UV Match does not use
it.
Use Cage—When on, bases projection on the
Projection mo difier’s cage sub-object. When off,
uses an offset instead. Default=on.
Offset—Enabled only when Use Cage is turned
off. Offset is the distance above the surface of the
source object from which normals are projected.
Default=10.0 units.
Resolve Hit group
The two radio buttons are f or scenes that have
semitransparent objects, in which case more than
onehitcanbefoundforeachray.Theremaining
controls in this group are additional projection
controls.
•
Clo se s t —If there are multiple hits, use the
closest object.
•
Furt he st—(The default.) If there are multiple
hits, use the farthest object.
Hit Only Matching Ma teria l ID—When on,
projection is only between material IDs that
match. Turningthisoptiononenablesasingle
map to contain normal bump projections from
different high-res s ource geometry. Default=off.