Creates a nurbs surface of degree du and dv with 3-dimensional euclidian control points which approximates a list of data points v by Multi Level B-Spline Approximation. i is the number of iterations which shall be performed. If the flag b is not zero the base rectangle in the xy-plane (= parametric domain) is chosen, so that it has minimal area, else it is chosen, so that its edges are parallel to the x- and y-axis.
i, b, du and dv are number nodes, and v is a typeless node to which the data points are connected.
In the C++ class hierarchy the class created by the NUBMBAS keyword is derived from a general trimmed nurbs surface class (see TNURBSURF, 6.7.22), so that it can be used at any places where a trimmed nurbs surface is expected (with the same number format and control point type of course)
The following variations of this keyword exist (some of them define the same internal structures, and are only defined to allow consistent naming conventions):
| Keyword | numbers |
| NUBMBAS | float |
| NUBMBAS_F | float |
| NUBMBAS_D | double |
| NUBMBAS_F_E3 | float |
| NUBMBAS_D_E3 | double |