8

Creating Surface Sub-Objects 1179
Seed 1 and Seed 2 —
The curve resides on the edge
closest to the two seed values. Adjust the seed
values to change the edge on which the curve
resides.
Replace Surface— This lets you replace the parent
surface. Click a button, then click a surface to
replace the original parent surface.
Creat ing Surface
Sub-Objects
SelectNURBSobject.>Modifypanel>CreateSurfaces
rollout
Select NURBS object. > NURBS toolbox
Keyboard > CTRL+T to toggle NURBS toolbox display
(Keyboard Shortcut Override Toggle must be on.)
Surfacesub-objectsareeitherindependentpoint
and CV sur faces (like the top-level point and
CV surfaces described in Point Surface and
CV Surface), or they are dependent surfaces.
Dependent surfaces a re surface sub-objects whose
geometry depends on other surfaces or curves
intheNURBSmodel. Whenyouchangethe
geometry of the original, parent surface or curve,
the dependent surface changes as well.
You create surface sub-objects using the Create
Surfaces rollout on the Modify panel for a NURBS
surface, or using the NURBS
toolbo x (page
1–1085)
.
Tip: Lathe and extrude surface sub-objects can
be based on only a single curve. If you have
dependentcurvesandwanttousethesetofcurves
(for example, two parents and a fi llet between
them)asthebasisofanextrudeorlathesurface,
firstgototheCurvesub-objectlevelanduseJoin
to connect the curves.
Creation operations for dependent sub-objects
require that you select one or more parent objects.
In general, you can click and drag, or click and
then click again. You can also use the H keyboard
shortcut to display a selec t-by-name dialog for
choosing the parent. (The
Keyboard Shortcut
Override Toggle (page 3–912)
button on the status
bar must b e on for H to work this way.)
Toolbox B uttons for Crea ting S ur f aces
Thesearethetoolboxbuttonsforcreatingsurface
sub-objects:
Create an independent CV surface sub-object
(page 1–1180)
.