Although NURBS curves
are analytically generated, in order to generate and display them
they must be approximated by line segments.
Curve approximation controls
are displayed in the creation parameters for curve objects, and
on a Curve Approximation rollout for NURBS models (top-level NURBS
objects). At the model level, approximation controls affect all
curve sub-objects in the model.
Curve approximation is
accomplished by segments. One or more line segments,
or steps, are used to approximate
each segment of the curve. For point curves, a segment of a curve
is the portion between one point and the next. For CV curves, the
segment is determined by the CV’s parametric
The transition from one CV curve segment to another isn’t visible
Curve approximation parameters
The maximum number of
line segments used to approximate each curve segment. If the curve
displays or renders with angles, increase this value. This control
is unavailable when Adaptive is on. Range=1 to 100.
Turn on this check box
to optimize the curve. When on, interpolation uses the specified
Steps value unless two segments are collinear, in which case they
are converted to a single segment. This control is unavailable when
Adaptive is on.
(The default.) Segments the
curve adaptively, based on its curvature. In other words, the curve
is assigned more segments where its curvature is greatest, and fewer
segments where its curvature is less.