9.5.2

236 • CHAPTER 7
OBJECTS MENU • NURBS • 237
Constant Cross Section
This option is enabled by default. It is ignored if a rail path is used. It causes the contour spline to be
scaled at hard edges in order to maintain a constant thickness throughout the sweep. The following
star-shaped path illustrates the effect.
Constant Cross Section enabled (left) and disabled (right).
Keep Segments
This setting is only used if you have changed the value for Growth. Its effect is, by and large, only
noticeable with animated growth. If the option is disabled, the animation growth is smooth. However,
if you enable Keep Segments, the sweep grows segment by segment. The positions of the segments
are determined by the path spline’s interpolation type (Type). An adaptive path spline will usually lead
to a jerky growth animation if Keep Segments is enabled.
2-Rail
The 2-Rail feature takes effect only if both the Use Rail Direction and Use Rail
Scale checkboxes are checked.
2-Rail enabled (left) and disabled (right).
If this option is enabled, the contour spline will be placed between the path and the rail; otherwise, the
rail controls the contour’s rotation about its Z-axis (provided Use Rail Direction is enabled).