Create Spline From Points

using System;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Splines;

namespace sc.modeling.splines.runtime.auxiliary
{
    public class CreateSplineFromPoints : MonoBehaviour
    {
        [Header("Input")]
        [Tooltip("Positional points in local-space")]
        public List<Vector3> points = new List<Vector3>()
        {
            new Vector3(-1f, 0f, -5f),
            new Vector3(1f, 0f, -2.5f),
            new Vector3(-1f, 0f, 0),
            new Vector3(1f, 0f, 2.5f),
            new Vector3(-1f, 0f, 5f),
        };

        [Space]

        [Header("Output")]
        public SplineContainer splineContainer;
        public bool smooth = true;

        private void Reset()
        {
            splineContainer = GetComponent<SplineContainer>();
            if (!splineContainer) splineContainer = this.gameObject.AddComponent<SplineContainer>();
        }

        private void OnValidate()
        {
            if (!splineContainer) return;

            int pointCount = points.Count;

            if (pointCount < 2) return;

            //First, delete all existing splines
            for (int s = 0; s < splineContainer.Splines.Count; s++)
            {
                splineContainer.RemoveSpline(splineContainer.Splines[s]);
            }

            Spline spline = new Spline(pointCount);

            for (int i = 0; i < pointCount; i++)
            {
                BezierKnot knot = new BezierKnot();
                knot.Position = points[i];
                knot.Rotation = Quaternion.identity;

                spline.Add(knot, smooth ? TangentMode.AutoSmooth : TangentMode.Linear);
            }

            //Automatically recalculate tangents
            spline.SetTangentMode(new SplineRange(0, spline.Count), smooth ? TangentMode.AutoSmooth : TangentMode.Linear);

            //Adding a spline automatically rebuilds the mesh
            splineContainer.AddSpline(spline);
        }

        private void OnDrawGizmosSelected()
        {
            if (!splineContainer) return;

            Gizmos.matrix = splineContainer.transform.localToWorldMatrix;
            foreach (Vector3 p in points)
            {
                Gizmos.DrawSphere(p, 0.25f);
            }
        }
    }
}