9

1212 Chapter 9: Surface Modeling
2-Rail Sweep Surface rollout (Modification time)
Rail Curves—Showsthenamesofthetwocurves
you chose to be the rails.
Replace Rail 1 and Replace Rail 2—Let you replace
therailcurves.Clickoneofthesebuttons,thenin
aviewportclickthecurvetouseasthenewrail.
Section Cur ves—Thislistshowsthenamesofthe
cross-section curves, in the order you click them.
You can select a curve by clicking its name in the
list. Viewports display the selected curve in blue.
Arrow Buttons—Usethesetochangetheorderof
sect ion curves in the list. Select a curve in the list,
and then use the arrows to move the selection up
or down.
Curve Properties group
These controls affect individual curves you select
in the Section Cur ves list, as opposed to propert ies
of the sweep surface in general. They are enabled
onlywhenyouhaveselectedacurveintheSection
Curves list.
Reverse—When set, reverses the direction of the
selected curve.
Start Point—Adjusts the position of the curve’s
start point. This can help eliminate unwanted
tw ists or "buckles" in the surface.
This control is disabled if the curve is not a closed
curve.
While you’re adjusting start points, a dotted
blue line is displayed between them, to show the
alignment. The surface is not displayed, so it
doesn’t slow down adjustment. When you release
the mouse button, the surface reappears.
Insert—Adds a cu rve to the section list. Click to
turn on Insert, then click the curve. The curve
is inserted before the selected cur ve. To insert a
curveattheend,firsthighlightthe"----End-----"
marker in the list.
Remove—Removes a curve from the list. Select the
curve in the list, and then click Remove.
Refine—Refines the 2-r a il s weep sur face. Click
to turn on Refine, then click an iso curve on the
surface. (As you drag the mouse over the surface,
the available sec tion curves are highlighted.) The
curve you click is converted to a CV curve and
inserted into the sweep and the section list. As
when you refine a point curve, refining a sweep
can change the curvature of the surface slightly.
Once you’ve refined the surface by adding a
cross-section curve, you can use Edit Curves to
change the curve.