NURBS Curve Classes

Independent Curves

The following classes provide the ability to create independent curves.

• NURBSCurve - This base class describes the properties of a NURBS curve. This includes its open/closed state, and number of trim points. The Evaluate() method is used to compute points and tangents on the curve.
• NURBSPointCurve - This class is derived from NURBSCurve. It defines a curve that uses points to describe its shape. All the points lie on the curve itself. There are methods to get/set the number of points in the curve, get/set the points themselves, refine the curve (add points without changing its shape), and to get/set the transformation matrix used by the curve to position it within a NURBSSet.
• NURBSCVCurve - This class is derived from NURBSCurve. It defines a curve that uses control vertices (CVs) to describe its shape. The CVs define a control lattice which surrounds the curve. This class has methods to close the curve, set its order, number of knots and number of CVs, and get/set the knots and CVs. There is also a method to add additional CVs to the curve.

Dependent Curves

A dependent curve is an object that depends on one or more other objects to define what it is. For example, a Blend Curve depends on the two parent curves that it blends between when it was created (as well as on its two tension parameters). The following classes are derived from NURBSCurve.

• NURBSBlendCurve - This class defines a dependent blend curve. A blend curve connects the specified end of one curve to the specified end of another, blending the curvature of the parents to create a smooth curve between them.
• NURBSOffsetCurve - This class defines a dependent offset curve. An offset curve is offset from the original, parent curve. It lies in the same plane as its parent, and is normal to the original.
• NURBSXFormCurve - This class defines a dependent transform (xform) curve. A transform curve is a copy of the original curve with a different position, rotation, or scale
• NURBSMirrorCurve - This class defines a dependent mirror curve. A mirror curve is similar to a mirror object that you create using the Mirror tool (on the 3ds Max toolbar) or the Mirror modifier. It is the original curve relfected about one or two axes.
• NURBSFilletCurve - This class defines a dependent fillet curve. A fillet is a curve that creates a circular arc corner between two parent curves.
• NURBSChamferCurve - This class defines a dependent chamfer curve. A chamfer curve creates a straight line corner between two parent curves.
• NURBSIsoCurve - This class defines a dependent iso curve. U and V iso curves are dependent curves created along lines of constant parameter value of a NURBS surface. Note the difference between "Iso Lines", which are a display artifact, and "Iso Curves" which are the dependent objects.