9

1206 Chapter 9: Surface Modeling
1-Rail Sweep Sur face rollout (creation time)
Rail Curve—Shows the name of the c urve you chose
to be the rail.
Replace Rail—(Disabled.)
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,
andthenusethearrowstomovetheselectionup
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—(Disabled.)
Remove—Removes a curve from the list. Select the
curve in the list, and then click Remove.
Refine—(Disabled.)
Replace—(D isabled.)
Sweep Parallel—When on, ensures that the sweep
surface’snormalisparalleltotherail.
Snap Cross-Sections—When on, cross-sect ion
curves are translated so they intersect the r ail.
The first cross sec tion is tr anslated to the start of
therail,andthelasttotheendoftherail. The
crosssectionsinthemiddlearetranslatedto
touch the rail at the closest point to the end of the
cross-section cu rves.
When Snap Cross-Sections is on, the sweep
followstherailcurveexactly.Thismakesiteasier
to construct 1-rail sweep surfaces.
Road-Like—When on, the sweep uses a constant
up-vector s o the cross sections twist uniformly