NURBS Point Classes
Independent Points:
Independent points are those that don't rely on other objects to define their location.
This is different than the dependent (or constrained) points described later.
- NURBSPoint - This class describes a point in 3 space. It is used as a base class for many of
the dependent points in the API. It has methods to set and get the point position
in various formats and floating point precisions. This is an abstract base class so
only objects that are subclasses of this class can be created.
- NURBSIndependentPoint - This class is derived from NURBSPoint. It is used to create an independent, free-standing point. There are methods to set
the position of the point in various floating point formats and operators to compare
points.
- NURBSControlVertex - This is a Control Vertex of a NURBS Curve or NURBS Surface. This class shares may
of the same properties as a NURBSPoint and has the added property of a rational weight. The weight value of a CV is rational.
That is, it is relative to other CVs in the curve or surface. Changing the weight
of all CVs at once has no effect, because this doesn't change the ratio between weights.
- NURBSTrimPoint - This class defines a point on a curve used to trim a portion of the curve from
the point towards one of the ends of the curve.
Dependent (Constrained) Points:
The following classes provide the ability to create dependent points. Dependent points
are related to the objects they depend on such that the relationship established initially
remains if the point, curve or surface moves. For example, a point can be created
such that it always remains a certain distance from another point. The options are
XYZ-relative, along a normal, or along a tangent (or set of tangents for a surface-dependent
constrained point).
All the following classes are derived from NURBSPoint.
- NURBSPointConstPoint - This class is used to create a dependent point that lies at a point or relative
to it. It is a point constrianed relative to another point. This can be a point used
to define a point surface or point curve, it can be a trim point, or just a point
in space.
- NURBSCurveConstPoint - This class is used to create a dependent point that lies on a curve or relative
to it.
- NURBSCurveCurveIntersectionPoint - This class is used to create a dependent point at the intersection of two curves.
- NURBSSurfConstPoint - This class is used to create a dependent point on a surface or related to it.