How do I get the nearest knot from a position on a spline?

Questions & Answers
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1

Hi, I’m trying to use the Splines package and I was wondering if there are some built-in methods to get the nearest knot from a given world space position on a spline. I’ve found SplineUtility.GetNearestPoint but it returns a point in space.

Thank you in advance!

2

After reading a bit the source code for the SplineUtility.GetNearestPoint, I decided for now to just iterate through all the knots in the spline to get the closest one.

I’m sharing the code just in case anyone needs it:

using UnityEngine.Splines;
using Unity.Mathematics;

public static class SplineExtensionMethods
{

	public static bool TryGetNearestKnotIndex(this ISpline spline, float3 position, out int nearestIndex)
	{
		nearestIndex = -1;

		if (spline == null || spline.Count == 0)
			return false;

		float minDistance = float.PositiveInfinity;
		NativeSpline nativeSpline = new NativeSpline(spline);

		for (int i = 0; i < spline.Count; i++)
		{
			float currentDistance = math.distance(nativeSpline[i].Position, position);

			if (currentDistance < minDistance)
			{
				minDistance = currentDistance;
				nearestIndex = i;
			}
		}

		return true;
	}

	public static bool TryGetNearestKnotIndex(this ISplineContainer container, float3 position, out SplineKnotIndex nearestIndex)
	{
		nearestIndex = SplineKnotIndex.Invalid;

		if (container == null || container.Splines.Count == 0)
			return false;

		float minDistance = float.PositiveInfinity;

		for (int i = 0; i < container.Splines.Count; i++)
		{
			NativeSpline spline = new NativeSpline(container.Splines[i]);

			for (int j = 0; j < spline.Count; j++)
			{
				float currentDistance = math.distance(spline[j].Position, position);

				if (currentDistance < minDistance)
				{
					minDistance = currentDistance;
					nearestIndex.Spline = i;
					nearestIndex.Knot = j;
				}
			}
		}

		return true;
	}

}
3

Bump, what is better way to find the closest knot to given position?