8

Modifying NURBS Models and Creating Sub-Objects 1083
Above: CV curve on surface
Below left: Using the curve to trim the surface
Below right: Using Flip Trim to change the trim ming
direction
To select an untrimmed surface:
1.
Make sure the Keyboard Shortcut Override
Toggle button on the status bar is on.
2. At the appropriate sub-object level or during
a replace p arent operation, press H.A
select-by-name dialog appears.
3. If the untrimmed version is selectable at this
level,thetrimmedversionappearsasa"tree,"
w ith a plu s sign next to it. Cl ick the plus sign to
expandthetree.Thechildistheuntrimmed
version. Highlight its name to select it.
Modif y ing NUR B S Models a nd
Creating Sub-Objects
You can edit NURBS immediately when you
enter the Modify panel. You don’t have to apply
a modifier, as you do for most kinds of 3ds Max
objects.
WhileyouareeditingaNURBSobjectonthe
Modify p a nel, you c an create sub-objects "on the
fly," without having to go back to the Create panel.
This is an exception to the way you usually use
3ds Max. The Modify panel for NURBS curve and
NURBSsurfaceobjectsincludesrolloutsthatlet
you c reate new NURBS sub-objec ts.
Example: Rollout for creating NURBS surface sub-objects
Tip: Another way to create curve and surface
sub-objectsistousethe
NURBS Creation Toolbox
(page 1–1085)
.
This is a summary of how to create sub-objects:
• An individual point sub-object is either an
independent point or a dependent point tied to
other NURBS geometry.
• Curve sub-objects are either independent point
curves or C V curves, or they are
dependent
(page 3–1022)
curves whose geometry is based
on other curves or surfaces already present in
the model. For example, a blend curve is a
dependent c urve sub-object that connects the
endpoints of two other curves.
• Surface sub-objects are either independent
point surfaces or CV surfaces, or they are
dependent (page 3–1022) surfaces whose
geometry is based on other surfaces or curves
already present in the model. For example, a