A 
    
Property which evaluates to a Cartesian3 vector
based on the velocity of the provided PositionProperty.
| Name | Type | Default | Description | 
|---|---|---|---|
| position | PositionProperty | optional The position property used to compute the velocity. | |
| normalize | Boolean | true | optional Whether to normalize the computed velocity vector. | 
Example:
//Create an entity with a billboard rotated to match its velocity.
const position = new Cesium.SampledProperty();
position.addSamples(...);
const entity = viewer.entities.add({
  position : position,
  billboard : {
    image : 'image.png',
    alignedAxis : new Cesium.VelocityVectorProperty(position, true) // alignedAxis must be a unit vector
  }
}));Members
readonly definitionChanged : Event
    Gets the event that is raised whenever the definition of this property changes.
    Gets a value indicating if this property is constant.
    Gets or sets whether the vector produced by this property
will be normalized or not.
position : Property|undefined
    Gets or sets the position property used to compute the velocity vector.
Methods
    Compares this property to the provided property and returns
    
true if they are equal, false otherwise.
| Name | Type | Description | 
|---|---|---|
| other | Property | optional The other property. | 
Returns:
true if left and right are equal, false otherwise.
getValue(time, result) → Cartesian3
    Gets the value of the property at the provided time.
    
| Name | Type | Description | 
|---|---|---|
| time | JulianDate | optional The time for which to retrieve the value. | 
| result | Cartesian3 | optional The object to store the value into, if omitted, a new instance is created and returned. | 
Returns:
    The modified result parameter or a new instance if the result parameter was not supplied.
    
