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1150 Chapter 9: Surface Modeling
Tex ture Channels group
Thecontrolsinthisgroupboxsupportmaterials,
includingtilingandpositioningmapping
coordinates on the surface.
Ma p Channel—Chooses a U V coordinates map
channel (page 3–966). Range=1 to 99. A single
surfacecanuseupto99texturechannels.
Default=1.
Gen. Mappi ng Coordina tes—Generates mapping
coordinates so you can apply mapped materials to
the surface. Each surface in a NURBS object has
its own set of mapping coordinates. Default=off.
U and V Offset—Offset mapping coordinates a long
the surface’s local U axis or V axis. That is, at
0.0(thedefault),themapbeginsattheUorV
origin. Increasing an Offset value moves the map
forward along that axis, and decreasing it moves it
backward. These parameters are animatable.
U and V Tiling—Control the tiling of UV mapping
coordinates; that is, the number of times a mapped
material’s map is repeated in the surface’s local
UaxisorVaxis.Default=1.0forbothaxes(no
tiling). These parameters are animatable.
Rotation Angle—Letsyouspecifyarotationangle
for the texture. This parameter is animatable.
Texture Corners group
Thecontrolsinthisgroupboxletyouexplicitly
set w hich texture surface UV values to use at the
corners of a surface. These controls are especially
useful when you are m atching the textures of
adjacent surfaces.
These controls are disabled unless Generate
Mapping Coordinates is on.
Corners r adio buttons—The four buttons
correspond to the four corners of the currently
selected sur face. When you choose a button, the
correspondingcornerishighlightedwithablue
box in 3D viewports, and the U and V spinners
are enabled.
UandV—Unavailableunlessyou’vechosenoneof
the Corners radio buttons. When available, you
use these spinners to set the U and V texture va lues
for the chosen corner.
By default, the U and V va lues for most surfaces
range from 0.0 to 1.0. For some k inds of geometry
converted to a NURBS surface, these ranges can
vary.
Texture Surface group
The controls in this group bo x let you choose
a method for mapping texture to the currently
selected NURB S surface sub-object, and to adjust
the parameters for some of the chosen methods.
These controls are available when Generate
Mapping Coordinates is on.
A texture surface is a surface associated with the
surface sub-object. The texture surface controls
how materials are mapped. In effect, changing
thetexturesurfacestretchesorotherwisechanges
the UV coordinates for the surface, altering the
mapping.
Mapscanshiftwithcertainsurfaceapproximation
methods. This effect is especially noticeable when
thesurfacehasanimatedCVs.Youcanreduceor
eliminate map s hifting by changing the mapping
method to User Defined.
Tip: Don’t use the UVW Map modifier to apply a
texture to an animated NURBS surface.
Default—Automatica lly gener ates a texture
surface. This method evenly distributes the texture
and attempts to compensate for stretching of the
surface.
Thedefaulttexturesurfacemethodhasno
additional controls.