## Overview

NurbsPositionInterpolator describes a 3D NURBS curve and outputs interpolated position values.

The NurbsPositionInterpolator node belongs to the **NURBS** component and its default container field is *children.* It is available since X3D version 3.0 or later.

## Hierarchy

1
2
3

+ X3DNode
+ X3DChildNode
+ NurbsPositionInterpolator

## Fields

### SFNode [in, out] **metadata** NULL [X3DMetadataObject]

Metadata are not part of the X3D world and not interpreted by the X3D browser, but they can be accessed via the ECMAScript interface.

### SFFloat [in] **set_fraction** (-∞,∞)

Setting fraction in range [0,1] selects input key for corresponding keyValue output, computing a 3D position on the curve.

### SFNode [in, out] **controlPoint** NULL [X3DCoordinateNode]

Input/Output field controlPoint.

### MFDouble [in, out] **knot** [ ] (-∞,∞)

*knot* vector, where size = number of control points + order of curve.

### SFInt32 [in, out] **order** 3 (2,∞)

Define order of surface by polynomials of degree = order-1.

### MFDouble [in, out] **weight** [ ] (-∞,∞)

Output values for linear interpolation, each corresponding to knots.

#### Hint

- Number of weights must match number of knots!

### SFVec3f [out] **value_changed**

Linearly interpolated output value determined by current key time and corresponding keyValue pair.

## Description

### Hint

- The SFNode controlPoints field can contain a single Coordinate or CoordinateDouble node.