Non-Uniform Rational Spline Base curve definition. NURBS3D has the following child elements:
| Child | Namespace | Type | Use | Cardinality | Choice | Description |
|---|---|---|---|---|---|---|
| ControlPtList | ocx | ocx:ControlPtList_T | req. | [1, 1] | False | List of control points (X,Y,Z) and their optional weights. The array length N=degree+1. A minimum of 2 control points is necessary to define a curve. |
| KnotVector | ocx | ocx:KnotVector_T | req. | [1, 1] | False | The knot-vector is a list of size m=+n-1 knots where p is the polynomial basis degree and n is the number of control points. The knot vector consists of a non-decreasing sequence of values. Knot multiplicities can be included. A knot multiplicity means that a knot value can be repeated up to p+1 times. |
| NURBSproperties | ocx | ocx:NURBSProperties_T | req. | [1, 1] | False | Properties of the basis functions in surface V direction. |
NURBS3D has the following attributes:
| Attribute | Namespace | Type | Use | Default | Fixed | Description |
|---|---|---|---|---|---|---|
| is2D | ocx | xs:boolean | opt. | false | Set to True if the Curve3D is given in 2D space. | |
| GUIDRef | ocx | ocx:guid | opt. | A globally unique ID referring to an entity in the authoring application. The sending application creates and holds the GUID. Used to establish a unique reference to an entity persistent between applications. | ||
| name | ocx | xs:string | opt. | An optional descriptive or display name. | ||
| id | ocx | xs:ID | req. | An identifier for an element unique within the scope of the XML file. Each id must be unique within a document. The attribute uses the standard XML 1.0 ID type as defined in the XML Schema specification. This attribute is required in many OCX XML elements and an application should generate them automatically. |