8
1208 Chapter 9: Sur face Modeling
Curve Properties group
These cont rols affect individual cur ves you select
in the S ec tion Curves list, as opposed to properties
of the sweep surface in general. They are enabled
only when you have selected a curve in the Section
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.
Thiscontrolisdisabledifthecurveisnotaclosed
cur ve.
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 su rface reappears.
Insert—(Disabled.)
Remove—Removes a curve from the list. Select the
curve in t he list, and then click Remove.
Refine—(Disabled.)
Replace—(Disabled.)
Sweep Parallel—When on, ensures that the sweep
surface’snormalisparalleltotherail.
Snap Cross-Sections—When on, cross-section
curves are translated so they intersect the rail.
The first cross sect ion is translated to the start of
the rail, and the last to the end of the r ail. The
crosssectionsinthemiddlearetranslatedto
touch the rail at the closest point to the end of the
cross-section curves.
When Snap Cross-Sections is on, the sweep
follows the rail cur ve exactly. This makes it easier
to construct 1-rail sweep surfaces.
Road-Like—When on, the sweep uses a constant
up-vector so the cross sect ions twist uniformly
as they travel along the rail. In other words, the
crosssectionsbanklikeacarfollowingaroad,ora
camera following a
path constraint (page 2–380)
.
Default=off.
When you edit the surface, you can control the
angle of banking . T he up-vector is d isplayed as
a yellow gizmo (similar to the gizmo that lathe
surfaces (page 1–1192)
use for the center of
rotation). To change the up-vector ang le, use
Rotate (page 1–420)
to change the gizmo’s angle.
Display While Creating—When on, the sweep
surfaceisdisplayedwhileyoucreateit. When
off,thesweepcanbecreatedmorequickly.
Default=off.
Flip Normals—Reverses the direction of the sweep’s
normals.