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CatmullRomSpline

CatmullRomSpline

new CatmullRomSpline

A Catmull-Rom spline is a cubic spline where the tangent at control points, except the first and last, are computed using the previous and next control points. Catmull-Rom splines are in the class C1.

Parameters:
Name Type Description
controlPoints Array The array of control points. Each element of the array should be an object with point and time properties.
firstTangent Cartesian3 The tangent of the curve at the first control point. If the tangent is not given, it will be estimated.
lastTangent Cartesian3 The tangent of the curve at the last control point. If the tangent is not given, it will be estimated.
Throws:
Example
// spline above the earth from Philadelphia to Los Angeles
var controlPoints = [
    {point: new Cartesian3(1235398.0, -4810983.0, 4146266.0), time: 0.0},
    {point: new Cartesian3(1372574.0, -5345182.0, 4606657.0), time: 1.5},
    {point: new Cartesian3(-757983.0, -5542796.0, 4514323.0), time: 3.0},
    {point: new Cartesian3(-2821260.0, -5248423.0, 4021290.0), time: 4.5},
    {point: new Cartesian3(-2539788.0, -4724797.0, 3620093.0), time: 6.0}
];
var spline = new CatmullRomSpline(controlPoints);
See:

Methods

evaluate

Evaluates the curve at a given time.

Parameters:
Name Type Description
time Number The time at which to evaluate the curve.
Throws:
  • DeveloperError : time is required.
  • DeveloperError : time must be in the range [a0, an], where a0 and an are the time properties of first and last elements in the array given during construction, respectively.
Returns:
Cartesian3 The point on the curve at the given time.
Example
// spline above the earth from Philadelphia to Los Angeles
var controlPoints = [
    {point: new Cartesian3(1235398.0, -4810983.0, 4146266.0), time: 0.0},
    {point: new Cartesian3(1372574.0, -5345182.0, 4606657.0), time: 1.5},
    {point: new Cartesian3(-757983.0, -5542796.0, 4514323.0), time: 3.0},
    {point: new Cartesian3(-2821260.0, -5248423.0, 4021290.0), time: 4.5},
    {point: new Cartesian3(-2539788.0, -4724797.0, 3620093.0), time: 6.0}
];
var spline = new CatmullRomSpline(controlPoints);

// some position above Los Angeles
var position = spline.evaluate(5.0);

getControlPoints

Returns the array of control points.

Returns:
Array The array of control points.

getEndTangent

Returns the tangent of the last control point.

Returns:
Cartesian3 The tangent of the last control point.
See:

getStartTangent

Returns the tangent of the first control point.

Returns:
Cartesian3 The tangent of the first control point.
See: