Class SplineUtility

A collection of methods for extracting information about Spline types.

Inheritance

Object

SplineUtility

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

CalculateLength(Spline, float4x4)

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

Declaration

public static float CalculateLength(Spline spline, float4x4 transform)

Parameters

Type	Name	Description
Spline	spline
float4x4	transform

Returns

Type	Description
Single

CurveToSplineInterpolation<T>(T, Single)

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

Declaration

public static float CurveToSplineInterpolation<T>(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

See Also

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

EvaluateDirection<T>(T, Single)

Return an interpolated direction at ratio t.

Declaration

public static float3 EvaluateDirection<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

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

EvaluateUpVector<T>(T, Single)

Evaluate an up vector of a spline at a specific t

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

GetBounds<T>(T)

Calculate the bounding box of a Spline.

Declaration

public static Bounds GetBounds<T>(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.

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

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

Declaration

public static float GetConvertedTime<T>(T spline, float time, PathIndexUnit originalTimeUnit, 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	time	The splineData time in the original PathIndexUnit.
PathIndexUnit	originalTimeUnit	The PathIndexUnit from the original time.
PathIndexUnit	targetPathUnit	The PathIndexUnit in which time should be converted.

Returns

Type	Description
Single	The time converted in the targetPathUnit.

Type Parameters

Name	Description
T

GetNearestPoint(NativeSpline, Ray, out float3, out Single, Int32, Int32)

Calculate the point on a spline nearest to a ray.

Declaration

public static float GetNearestPoint(NativeSpline spline, Ray ray, out float3 nearest, out float time, int resolution = 4, int iterations = 2)

Parameters

Type	Name	Description
NativeSpline	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	time	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.

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 time, 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	time	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 input point to nearest point on spline.

Type Parameters

Name	Description
T

GetNormalizedTime<T>(T, Single, PathIndexUnit)

Given a time value using a certain PathIndexUnit type, calculate the normalized time value regarding a specific spline.

Declaration

public static float GetNormalizedTime<T>(T spline, float time, PathIndexUnit originalTimeUnit)
    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	time	The time to normalize in the original PathIndexUnit.
PathIndexUnit	originalTimeUnit	The PathIndexUnit from the original time.

Returns

Type	Description
Single	The normalized time.

Type Parameters

Name	Description
T

GetSegmentCount(Single, Int32)

Use this function to calculate the number of segments for a given spline length and resolution.

Declaration

public static int GetSegmentCount(float length, int resolution)

Parameters

Type	Name	Description
Single	length	A distance value in PathIndexUnit.
Int32	resolution	A value used to calculate the number of segments for a length. This is calculated as max(MIN_SEGMENTS, min(MAX_SEGMENTS, sqrt(length) * resolution)).

Returns

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

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

SplineToCurveInterpolation<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 SplineToCurveInterpolation<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