| Name | Type | Use | Description |
| degree | xs:int | required | B-spline degree p is the highest exponent used in the polynomial basis function. The B-spline order is always p+1. Defined as p = m - n - 1 if not given explicitly where m is the number of knots and n is the number of control points. |
| form | ocx:curveForm_enum | optional | The NURBS curve form (Open, Closed, or Periodic). |
| isRational | xs:boolean | optional | The default is non-rational basis functions (isRational=false). Rational refers to the underlying mathematical representation. This property allows NURBS to represent exact conics (such as parabolic curves, circles, and ellipses) in addition to free-form curves. To define conical curve types set isRational=true. |
| numCtrlPts | xs:long | required | Number of control points in the curve direction or the surface grid u or v direction. |
| numKnots | xs:long | required | numKnots: m=(p+n-1) numbers, where p is the polynomial basis degree and n is the number of control points. |