9

1204 Chapter 9: Surface Modeling
or CVs of the curve are displayed, as well as the
control lattice if the curve is a CV curve. You can
now transform or otherwise change the points
or CVs as if you were at the Point or Curve CV
sub-object level. To finish editing the curve, click
to turn off Edit Curves.
When you turn on Edit Curves, all applicable
rollouts for the selected cur ves are displayed,
including the Curve Common rollout, the CV
or Point rollout (depending on the curve type),
and the CV Curve or Point Curve rollout. These
rollouts appear beneath the U Loft rollout. They
let you edit the loft curves and their points or CVs
without having to switch sub-object levels.
Tip: When you edit curves in a UV loft, turning
off display of the UV loft itself can make the
curves easier to see and improve per formance. Use
Ctrl+D (while the Keyboard Shor tcut Override
Toggle button (page 3–872) is on) to toggle display
of dependent sub-objects, including UV lofts.
The UV loft surface can deviate from the curve
if you edit a curve in a UV loft by increasing the
weight of the curve CVs. You can work around
this by refining the curve at the point where the
surface deviates.
1-R ail Sweep Sur face
SelectNURBSobject. >Modifypanel>CreateSurfaces
rollout > D ependent Surfaces group box > 1-Rail
Select NURBS object. > Modify panel > NURBS toolbox >
Create 1-R a il Sweep button
Sweep surfaces are constructed from curves. A
1-rail sweep surface uses at least two curves.
One curve, the "rail," defines one edge of the
surface. The other cur ves define the surface’s cross
sections.
1-rail sweep surface
Changing the p osition of the rail can change the shape of the
surface.
The cross-section curves should intersect the rail
curve. If the cross-sec tions don’t intersect the rail,
theresultingsurfaceisunpredictable.Inaddition,
the initial point of t he rail and the initial point of
the first cross-section curve must be coincident.
Use NURBS Snaps (page 2–41) to accomplish this.
Automatic Cur ve Attachment
When you create a 1-rail sweep, you can select
curves that are not already sub-objects of the active
NURBS mo del. You can select another curve or
spline (page 1–266) object in the scene. When you
select that curve, it attaches to the current object as
if you had used the Attach button (page 1–1120).
Wa rn in g : If the curve you attach is a sub-object of
anotherNURBSmodel,theentiremodel(thatis,the
curve’s parent NURBS object) is attached as well.
Asyoumovethemouseoveracurvethatisnot
part of the active NURBS object, the cursor
changes shape to indicate that you can pick the
curve, but the curve is not highlighted in blue.
Procedures
To create a 1-rail sweep:
1.
Createthecurvesthatdefinethesurfaceyou
want to create.