Class SplineUtility

A collection of methods for extracting information about Spline types.

Inheritance

Object

SplineUtility

Inherited Members

Object.ToString()

Object.Equals(Object)

Object.Equals(Object, Object)

Object.ReferenceEquals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Namespace: UnityEngine.Splines

Syntax

public static class SplineUtility

Fields

DrawResolutionDefault

The default resolution used when unrolling a curve to draw a preview in the Scene View.

Pick resolution is used when determining how many segments are required to unroll a curve. Unrolling is the process of calculating a series of line segments to approximate a curve. Some functions in SplineUtility allow you to specify a resolution. Lower resolution means fewer segments, while higher resolutions result in more segments. Use lower resolutions where performance is critical and accuracy is not paramount. Use higher resolution where a fine degree of accuracy is necessary and performance is less important.

Declaration

public const int DrawResolutionDefault = 10

Field Value

Type	Description
Int32

PickResolutionDefault

The default resolution used when unrolling a curve to hit test while picking (selecting a spline with a cursor).

Pick resolution is used when determining how many segments are required to unroll a curve. Unrolling is the process of calculating a series of line segments to approximate a curve. Some functions in SplineUtility allow you to specify a resolution. Lower resolution means fewer segments, while higher resolutions result in more segments. Use lower resolutions where performance is critical and accuracy is not paramount. Use higher resolution where a fine degree of accuracy is necessary and performance is less important.

Declaration

public const int PickResolutionDefault = 4

Field Value

Type	Description
Int32

PickResolutionMax

The maximum resolution allowed when unrolling a curve to hit test while picking (selecting a spline with a cursor).

Pick resolution is used when determining how many segments are required to unroll a curve. Unrolling is the process of calculating a series of line segments to approximate a curve. Some functions in SplineUtility allow you to specify a resolution. Lower resolution means fewer segments, while higher resolutions result in more segments. Use lower resolutions where performance is critical and accuracy is not paramount. Use higher resolution where a fine degree of accuracy is necessary and performance is less important.

Declaration

public const int PickResolutionMax = 64

Field Value

Type	Description
Int32

PickResolutionMin

The minimum resolution allowable when unrolling a curve to hit test while picking (selecting a spline with a cursor).

Pick resolution is used when determining how many segments are required to unroll a curve. Unrolling is the process of calculating a series of line segments to approximate a curve. Some functions in SplineUtility allow you to specify a resolution. Lower resolution means fewer segments, while higher resolutions result in more segments. Use lower resolutions where performance is critical and accuracy is not paramount. Use higher resolution where a fine degree of accuracy is necessary and performance is less important.

Declaration

public const int PickResolutionMin = 2

Field Value

Type	Description
Int32

Methods

AddSpline<T>(T)

Creates a new spline and adds it to the ISplineContainer.

Declaration

public static Spline AddSpline<T>(this T container)
    where T : ISplineContainer

Parameters

Type	Name	Description
T	container	The target container.

Returns

Type	Description
Spline	Returns the spline that was created and added to the container.

Type Parameters

Name	Description
T	A type that implements ISplineContainer.

CalculateLength<T>(T, float4x4)

Calculate the length of a spline when transformed by a matrix.

Declaration

public static float CalculateLength<T>(this T spline, float4x4 transform)
    where T : ISpline

Parameters

Type	Name	Description
T	spline
float4x4	transform

Returns

Type	Description
Single

Type Parameters

Name	Description
T	A type implementing ISpline.

ConvertIndexUnit<T>(T, Single, PathIndexUnit)

Given a normalized interpolation ratio, calculate the associated interpolation value in another targetPathUnit regarding a specific spline.

Declaration

public static float ConvertIndexUnit<T>(this T spline, float t, PathIndexUnit targetPathUnit)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The Spline to use for the conversion, this is necessary to compute Normalized and Distance PathIndexUnits.
Single	t	Normalized interpolation ratio (0 to 1).
PathIndexUnit	targetPathUnit	The PathIndexUnit to which 't' should be converted.

Returns

Type	Description
Single	The interpolation value converted to targetPathUnit.

Type Parameters

Name	Description
T	A type implementing ISpline.

ConvertIndexUnit<T>(T, Single, PathIndexUnit, PathIndexUnit)

Given an interpolation value using a certain PathIndexUnit type, calculate the associated interpolation value in another targetPathUnit regarding a specific spline.

Declaration

public static float ConvertIndexUnit<T>(this T spline, float t, PathIndexUnit fromPathUnit, PathIndexUnit targetPathUnit)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The Spline to use for the conversion, this is necessary to compute Normalized and Distance PathIndexUnits.
Single	t	Interpolation in the original PathIndexUnit.
PathIndexUnit	fromPathUnit	The PathIndexUnit for the original interpolation value.
PathIndexUnit	targetPathUnit	The PathIndexUnit to which 't' should be converted.

Returns

Type	Description
Single	The interpolation value converted to targetPathUnit.

Type Parameters

Name	Description
T	A type implementing ISpline.

CurveToSplineT<T>(T, Single)

Given an interpolation value for a curve, calculate the relative normalized spline interpolation.

Declaration

public static float CurveToSplineT<T>(this T spline, float curve)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The target spline.
Single	curve	A curve index and normalized interpolation. The curve index is represented by the integer part of the float, and interpolation is the fractional part. This is the format used by Knot.

Returns

Type	Description
Single	An interpolation value relative to normalized Spline length (0 to 1).

Type Parameters

Name	Description
T	A type implementing ISpline.

See Also

SplineToCurveT<T>(T, Single, out Single)

Evaluate<T>(T, Single, out float3, out float3, out float3)

Compute interpolated position, direction and upDirection at ratio t. Calling this method to get the 3 vectors is faster than calling independently EvaluatePosition, EvaluateDirection and EvaluateUpVector for the same time t as it reduces some redundant computation.

Declaration

public static bool Evaluate<T>(this T spline, float t, out float3 position, out float3 tangent, out float3 upVector)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The spline to interpolate.
Single	t	A value between 0 and 1 representing the ratio along the curve.
float3	position	Output variable for the float3 position at t.
float3	tangent	Output variable for the float3 tangent at t.
float3	upVector	Output variable for the float3 up direction at t.

Returns

Type	Description
Boolean	Boolean value, true if a valid set of output variables as been computed.

Type Parameters

Name	Description
T	A type implementing ISpline.

EvaluateAcceleration<T>(T, Single)

Return an interpolated acceleration at ratio t.

Declaration

public static float3 EvaluateAcceleration<T>(this T spline, float t)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The spline to interpolate.
Single	t	A value between 0 and 1 representing the ratio along the curve.

Returns

Type	Description
float3	An acceleration on the spline.

Type Parameters

Name	Description
T	A type implementing ISpline.

EvaluateCurvature<T>(T, Single)

Return an interpolated curvature at ratio t.

Declaration

public static float EvaluateCurvature<T>(this T spline, float t)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The spline to interpolate.
Single	t	A value between 0 and 1 representing the ratio along the curve.

Returns

Type	Description
Single	A curvature on the spline.

Type Parameters

Name	Description
T	A type implementing ISpline.

EvaluateCurvatureCenter<T>(T, Single)

Return the curvature center at ratio t. The curvature center represents the center of the circle that is tangent to the curve at t. This circle is in the plane defined by the curve velocity (tangent) and the curve acceleration at that point.

Declaration

public static float3 EvaluateCurvatureCenter<T>(this T spline, float t)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The spline to interpolate.
Single	t	A value between 0 and 1 representing the ratio along the curve.

Returns

Type	Description
float3	A point representing the curvature center associated to the position at t on the spline.

Type Parameters

Name	Description
T	A type implementing ISpline.

EvaluatePosition<T>(T, Single)

Return an interpolated position at ratio t.

Declaration

public static float3 EvaluatePosition<T>(this T spline, float t)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The spline to interpolate.
Single	t	A value between 0 and 1 representing the ratio along the curve.

Returns

Type	Description
float3	A position on the spline.

Type Parameters

Name	Description
T	A type implementing ISpline.

EvaluateTangent<T>(T, Single)

Return an interpolated direction at ratio t.

Declaration

public static float3 EvaluateTangent<T>(this T spline, float t)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The spline to interpolate.
Single	t	A value between 0 and 1 representing the ratio along the curve.

Returns

Type	Description
float3	A direction on the spline.

Type Parameters

Name	Description
T	A type implementing ISpline.

EvaluateUpVector<T>(T, Single)

Evaluate the normal (up) vector of a spline.

Declaration

public static float3 EvaluateUpVector<T>(this T spline, float t)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The NativeSpline to evaluate.
Single	t	A value between 0 and 1 representing a percentage of the curve.

Returns

Type	Description
float3	An up vector

Type Parameters

Name	Description
T	A type implementing ISpline.

GetAutoSmoothKnot(float3, float3, float3)

Gets a BezierKnot with its tangents and rotation calculated using the previous and next knot positions.

Declaration

public static BezierKnot GetAutoSmoothKnot(float3 position, float3 previous, float3 next)

Parameters

Type	Name	Description
float3	position	The position of the knot.
float3	previous	The knot that immediately precedes the requested knot.
float3	next	The knot that immediately follows the requested knot.

Returns

Type	Description
BezierKnot	A BezierKnot with tangent and rotation values calculated from the previous and next knot positions.

GetAutoSmoothKnot(float3, float3, float3, float3)

Gets a BezierKnot with its tangents and rotation calculated using the previous and next knot positions.

Declaration

public static BezierKnot GetAutoSmoothKnot(float3 position, float3 previous, float3 next, float3 normal)

Parameters

Type	Name	Description
float3	position	The position of the knot.
float3	previous	The knot that immediately precedes the requested knot.
float3	next	The knot that immediately follows the requested knot.
float3	normal	The normal vector of the knot.

Returns

Type	Description
BezierKnot	A BezierKnot with tangent and rotation values calculated from the previous and next knot positions.

GetBounds<T>(T)

Calculate the bounding box of a Spline.

Declaration

public static Bounds GetBounds<T>(this T spline)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The spline for which to calculate bounds.

Returns

Type	Description
Bounds	The bounds of a spline.

Type Parameters

Name	Description
T	A type implementing ISpline.

GetBounds<T>(T, float4x4)

Creates a bounding box for a spline.

Declaration

public static Bounds GetBounds<T>(this T spline, float4x4 transform)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The spline to calculate bounds for.
float4x4	transform	The matrix to transform the spline's elements with.

Returns

Type	Description
Bounds	The bounds of a spline.

Type Parameters

Name	Description
T	A type implementing ISpline.

GetCatmullRomTangent(float3, float3)

Calculates a tangent from the previous and next knot positions.

Declaration

public static float3 GetCatmullRomTangent(float3 previous, float3 next)

Parameters

Type	Name	Description
float3	previous	The position of the previous BezierKnot.
float3	next	The position of the next BezierKnot.

Returns

Type	Description
float3	Returns a tangent calculated from the previous and next knot positions.

GetCurveCount<T>(T)

Calculates the number of curves in a spline.

Declaration

public static int GetCurveCount<T>(this T spline)
    where T : ISpline

Parameters

Type	Name	Description
T	spline

Returns

Type	Description
Int32	The number of curves in a spline.

Type Parameters

Name	Description
T	A type implementing ISpline.

GetNearestPoint<T>(T, float3, out float3, out Single, Int32, Int32)

Calculate the point on a spline nearest to a point.

Declaration

public static float GetNearestPoint<T>(T spline, float3 point, out float3 nearest, out float t, int resolution = 4, int iterations = 2)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The input spline to search for nearest point.
float3	point	The input point to compare.
float3	nearest	The point on a spline nearest to the input point. The accuracy of this value is affected by the resolution.
Single	t	The normalized interpolation ratio corresponding to the nearest point.
Int32	resolution	Affects how many segments to split a spline into when calculating the nearest point. Higher values mean smaller and more segments, which increases accuracy at the cost of processing time. The minimum resolution is defined by PickResolutionMin, and the maximum is defined by PickResolutionMax. In most cases, the default resolution is appropriate. Use with to fine tune point accuracy.
Int32	iterations	The nearest point is calculated by finding the nearest point on the entire length of the spline using to divide into equally spaced line segments. Successive iterations will then subdivide further the nearest segment, producing more accurate results. In most cases, the default value is sufficient, but if extreme accuracy is required this value can be increased to a maximum of PickResolutionMax.

Returns

Type	Description
Single	The distance from input point to nearest point on spline.

Type Parameters

Name	Description
T	A type implementing ISpline.

GetNearestPoint<T>(T, Ray, out float3, out Single, Int32, Int32)

Calculate the point on a spline nearest to a ray.

Declaration

public static float GetNearestPoint<T>(T spline, Ray ray, out float3 nearest, out float t, int resolution = 4, int iterations = 2)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The input spline to search for nearest point.
Ray	ray	The input ray to search against.
float3	nearest	The point on a spline nearest to the input ray. The accuracy of this value is affected by the resolution.
Single	t	The normalized time value to the nearest point.
Int32	resolution	Affects how many segments to split a spline into when calculating the nearest point. Higher values mean smaller and more segments, which increases accuracy at the cost of processing time. The minimum resolution is defined by PickResolutionMin, and the maximum is defined by PickResolutionMax. In most cases, the default resolution is appropriate. Use with to fine tune point accuracy.
Int32	iterations	The nearest point is calculated by finding the nearest point on the entire length of the spline using to divide into equally spaced line segments. Successive iterations will then subdivide further the nearest segment, producing more accurate results. In most cases, the default value is sufficient, but if extreme accuracy is required this value can be increased to a maximum of PickResolutionMax.

Returns

Type	Description
Single	The distance from ray to nearest point.

Type Parameters

Name	Description
T	A type implementing ISpline.

GetNormalizedInterpolation<T>(T, Single, PathIndexUnit)

Given an interpolation value in any PathIndexUnit type, calculate the normalized interpolation ratio value relative to a Spline.

Declaration

public static float GetNormalizedInterpolation<T>(T spline, float t, PathIndexUnit originalPathUnit)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The Spline to use for the conversion, this is necessary to compute Normalized and Distance PathIndexUnits.
Single	t	The 't' value to normalize in the original PathIndexUnit.
PathIndexUnit	originalPathUnit	The PathIndexUnit from the original 't'.

Returns

Type	Description
Single	The normalized interpolation ratio (0 to 1).

Type Parameters

Name	Description
T	A type implementing ISpline.

GetPointAtLinearDistance<T>(T, Single, Single, out Single)

Given a Spline and interpolation ratio, calculate the 3d point at a linear distance from point at spline.EvaluatePosition(t). Returns the corresponding time associated to this 3d position on the Spline.

Declaration

public static float3 GetPointAtLinearDistance<T>(this T spline, float fromT, float relativeDistance, out float resultPointT)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The Spline on which to compute the point.
Single	fromT	The Spline interpolation ratio 't' (normalized) from which the next position need to be computed.
Single	relativeDistance	The relative distance at which the new point should be placed. A negative value will compute a point at a 'resultPointTime' previous to 'fromT' (backward search).
Single	resultPointT	The normalized interpolation ratio of the resulting point.

Returns

Type	Description
float3	The 3d point from the spline located at a linear distance from the point at t.

Type Parameters

Name	Description
T	A type implementing ISpline.

GetSubdivisionCount(Single, Int32)

Gets the number of subdivisions for a spline length and resolution.

Declaration

public static int GetSubdivisionCount(float length, int resolution)

Parameters

Type	Name	Description
Single	length	The length of the spline to consider.
Int32	resolution	The resolution to consider. Higher resolutions result in more precise representations. However, higher resolutions have higher performance requirements.

Returns

Type	Description
Int32	The number of subdivisions as calculated for given length and resolution.

LinkKnots<T>(T, SplineKnotIndex, SplineKnotIndex)

Links two knots in an ISplineContainer. The two knots can be on different splines, but both must be in the referenced SplineContainer. If these knots are linked to other knots, all existing links are kept and updated.

Declaration

public static void LinkKnots<T>(this T container, SplineKnotIndex knotA, SplineKnotIndex knotB)
    where T : ISplineContainer

Parameters

Type	Name	Description
T	container	The target SplineContainer.
SplineKnotIndex	knotA	The first knot to link.
SplineKnotIndex	knotB	The second knot to link.

Type Parameters

Name	Description
T	A type that implements ISplineContainer.

Next<T>(T, Int32)

Gets the BezierKnot after spline[index]. This method uses the Count and Closed properties to ensure that it returns the correct knot.

Declaration

public static BezierKnot Next<T>(this T spline, int index)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The spline to consider.
Int32	index	The current index to consider.

Returns

Type	Description
BezierKnot	The knot after the knot at spline[index].

Type Parameters

Name	Description
T	A type that implements ISpline.

NextIndex<T>(T, Int32)

Gets the index of a knot that follows a spline index. This method uses the Count and Closed properties to ensure that it returns the correct index of the knot.

Declaration

public static int NextIndex<T>(this T spline, int index)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The spline to consider.
Int32	index	The current index to consider.

Returns

Type	Description
Int32	The knot index after index on the considered spline.

Type Parameters

Name	Description
T	A type that implements ISpline.

Previous<T>(T, Int32)

Gets the BezierKnot before spline[index]. This method uses the Count and Closed properties to ensure that it returns the correct knot.

Declaration

public static BezierKnot Previous<T>(this T spline, int index)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The spline to consider.
Int32	index	The current index to consider.

Returns

Type	Description
BezierKnot	The knot before the knot at spline[index].

Type Parameters

Name	Description
T	A type that implements ISpline.

PreviousIndex<T>(T, Int32)

Gets the index of a knot that precedes a spline index. This method uses the Count and Closed properties to ensure that it returns the correct index of the knot.

Declaration

public static int PreviousIndex<T>(this T spline, int index)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The spline to consider.
Int32	index	The current index to consider.

Returns

Type	Description
Int32	Returns a knot index that precedes the index on the considered spline.

Type Parameters

Name	Description
T	A type that implements ISpline.

RemoveSpline<T>(T, Spline)

Removes a spline from a ISplineContainer.

Declaration

public static bool RemoveSpline<T>(this T container, Spline spline)
    where T : ISplineContainer

Parameters

Type	Name	Description
T	container	The target SplineContainer.
Spline	spline	The spline to remove from the SplineContainer.

Returns

Type	Description
Boolean	Returns true if the spline was removed from the container.

Type Parameters

Name	Description
T	A type that implements ISplineContainer.

RemoveSplineAt<T>(T, Int32)

Removes a spline from a ISplineContainer.

Declaration

public static bool RemoveSplineAt<T>(this T container, int splineIndex)
    where T : ISplineContainer

Parameters

Type	Name	Description
T	container	The target container.
Int32	splineIndex	The index of the spline to remove from the SplineContainer.

Returns

Type	Description
Boolean	Returns true if the spline was removed from the container.

Type Parameters

Name	Description
T	A type that implements ISplineContainer.

SetLinkedKnotPosition<T>(T, SplineKnotIndex)

Sets the position of all knots linked to the knot at index in an ISplineContainer to the same position.

Declaration

public static void SetLinkedKnotPosition<T>(this T container, SplineKnotIndex index)
    where T : ISplineContainer

Parameters

Type	Name	Description
T	container	The target container.
SplineKnotIndex	index	The SplineKnotIndex of the knot to use to synchronize the positions.

Type Parameters

Name	Description
T	A type that implements ISplineContainer.

SetPivot(SplineContainer, Vector3)

Reset a transform position to a position while keeping knot positions in the same place. This modifies both knot positions and transform position.

Declaration

public static void SetPivot(SplineContainer container, Vector3 position)

Parameters

Type	Name	Description
SplineContainer	container	The target spline.
Vector3	position	The point in world space to move the pivot to.

SplineToCurveT<T>(T, Single, out Single)

Given a normalized interpolation (t) for a spline, calculate the curve index and curve-relative normalized interpolation.

Declaration

public static int SplineToCurveT<T>(this T spline, float splineT, out float curveT)
    where T : ISpline

Parameters

Type	Name	Description
T	spline	The target spline.
Single	splineT	A normalized spline interpolation value to be converted into curve space.
Single	curveT	A normalized curve interpolation value.

Returns

Type	Description
Int32	The curve index.

Type Parameters

Name	Description
T	A type implementing ISpline.

UnlinkKnots<T>(T, IReadOnlyList<SplineKnotIndex>)

Unlinks several knots from an ISplineContainer. A knot in knots disconnects from other knots it was linked to.

Declaration

public static void UnlinkKnots<T>(this T container, IReadOnlyList<SplineKnotIndex> knots)
    where T : ISplineContainer

Parameters

Type	Name	Description
T	container	The target SplineContainer.
IReadOnlyList<SplineKnotIndex>	knots	The knot to unlink.

Type Parameters

Name	Description
T	A type implementing ISplineContainer.