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1206 Chapter 9: Sur face Modeling
1-rail sweep surface
Changing the position of the rail can change the shape of
the surface.
The cross-section curves should intersect t he rail
curve. If the c ross-sec tions don’t intersect the rai l,
the resulting surface is u npredictable. In addition,
the initial point of the rail and the initial point of
the first cross-section curve must be coincident.
Use
NURBS Snaps (page 2–38) to accomplish this.
Automatic Cur ve Att achment
When you create a 1-rail sweep, you can select
curves that are not a lready sub-objects of the ac tive
NURBS model. You can select another curve or
spline (page 1–261) object in the scene. When you
select that cu rve, it attaches to the current object as
if you had used the
Attach button (page 1–1121) .
Wa rni ng: If the curve you attach is a sub-object of
anotherNURBSmodel,theentiremodel(thatis,the
curve’sparentNURBSobject)isattachedaswell.
Asyoumovethemouseoveracurvethatisnot
part of the active NURBS object, the cursor
changes shape to indicate that you can pick the
cur ve, but the curve is not highlig hted in blue.
Pr ocedur es
To create a 1 -ra il sweep:
1.
Create the curves that define the surface you
want to create.
2. Clicktoturnon1RailSweepinthe
toolbo x or on the Create Surfaces rollout.
3. Click the curve to use as the rail, then click each
of the cross-sect ion curves. Ri g ht-click to end
creation.
The sweep is interpolated smoothly between
the cross sections, following the outline defined
by the rail.
As you click curves, their names appear in
the lists on the 1 Rail Sweep Surface creation
rollout. The order in which you click the curves
can affect the shape of the sweep surface.