8

1092 Chapter 9: Sur face Modeling
NUR B S S election M odif ier
The NURBS Surface Selection (NSurf S el) (page
1–740)
lets you place a NURBS sub-object
selectiononthemodifierstack. Thisletsyou
modify only the selected sub-objects. Also,
selected curve sub-objects are
Shape (page 1–257)
objects that you can use as paths and motion
trajectories.
NSurf Sel c an select any kind of NURBS sub-object
except imports. Each sub-object select ion is of one
sub-object level only.
Procedure
To use a NURBS select modifier:
1.
With a NURBS object selected, go to the
Modify panel and apply NSurf Sel.
The selection modifier has no controls at the
object level.
2. Click to open the modifier’s hierarchy, and
choose a sub-object level.
The selection modifier has the same selection
controls you see for the corresponding
sub-object type.
While applying t he modifier, you can also select
NURBS sub-objec ts by name. Turn on the
K eyboard Shortcut Override Toggle button on
the st atus bar, and then press the H key . This
displays a select-by-name dialog that lists only
sub-objectsatthecurrentlevel.Chooseoneor
more objec t s in the list, and then click S elect.
Press CTR L +H to have the select-by-name
dialog list only objects directly beneath the
mouse cursor.
3. Use the selection controls to create a select ion
set of the chosen sub-object type.
With the NSurf Sel modifier, you can select
NURBS sub-objects at any level except imports.
Note: To select point, curve, or curve CV
sub-objects,youmustgototheNURBSobjectand
turn on Relational Stack.
Once you have used the modifier to create the
selection, you can apply other modifiers to it. If
the selected sub-object is a curve, you can a lso use
it as a path or trajectory.
Note: NSurf Sel doesn’t support copy and paste
of select ions as Mesh Select does. Copy ing and
pastingmeshselectionsisbasedonvertexindexes.
NURBS selections are based on object IDs, which
areuniquetoeachmodel.
NUR B S a nd Ani mation
In general, you animate NURBS c urves and
NURBS surfaces by tur ning on the Auto Key
button and transforming sub-object attributes
such as CV or point positions, by animating
the p ar ameters that control dependent NURBS
objects, and so on. You can’t animate NURBS
object creation or creation parameters, or
fundamental changes to NU RBS geometry such
as adding or deleting CVs or points, attaching
objects, and s o on.
Tip: To improve p er formance w hi le you animate
your scene, make the surfaces in your NURBS
model
nonrelational surfaces (page 1–1118) .
Modifiers treat nonrelational sur faces as if they
were independent CV surfaces: you can animate
the scene more efficiently, and then turn relational
modeling back on before you render.
Some NURBS editing operations remove
animation controllers.
Operations that R emove Animation
The following operations remove animation from
a NURBS object or sub-object:
• Make Independent