NURBS (Non-Uniform Rational B-Spline) is a mathematical model that is used to create curves and surfaces based on B-spline geometry. These surfaces are defined by a set of 3D vertices of the B-splines that form an M*N array, where M is the count of rows and N is the count of columns.
Mathematically the NURBS surface of degree (p,q) can be defined by:
where Ni,p and Nj,q are the basic functions of B-splines in both directions, Pi,j are the control points and wi,j are their weights, and m and n are the number of control points in the u- and v-directions respectively.
For working with NURBS surfaces, use the OdDbNurbSurface class, which represents
a NURBS surface entity and allows users to access a NURBS surface and manipulate
its properties. The OdDbNurbSurfacePtr class is the typified smart pointer to
an instance of this entity and is used for storing and passing references to
the NURBS surface objects.
To create and initialize a new instance of NURBS surfaces, see Overview of Specific Entities.
See Also
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