在网上看到一个平滑算法，很好用，经过测试它的效率很高，Chaikin 函数调用2-3次会获得一个相对较好的曲线。算法链接
原理是不断的裁切三角形让其分裂成2个三角，2个三角变成4个，以此类推，最终会越来越平滑从而接近一个圆。

裁切范例

平滑算法如下：

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using UnityEngine;
using System.Collections;

[RequireComponent(typeof(LineRenderer))]
public class SmoothAlgorithm : MonoBehaviour
{

    private float minRadius = 1.5f;
    private float maxRadius = 3.5f;
    private int num = 25;
    private LineRenderer lr;
    private Vector3[] points;

    void Start()
    {
        lr = GetComponent<LineRenderer>();
        GenerateRandomPath();
        SetLR(points);
    }

    void GenerateRandomPath()
    {
        points = new Vector3[num];

        float angle = 360.0f / num;

        for (int i = 0; i < num; i++)
        {
            points[i] = Quaternion.AngleAxis((angle * i), Vector3.forward) * Vector3.up * Random.Range(minRadius, maxRadius);
        }
    }

    void SetLR(Vector3[] pts)
    {
        lr.SetVertexCount(pts.Length);
        for (int i = 0; i < pts.Length; i++)
        {
            lr.SetPosition(i, pts[i]);
        }
    }

    void Update()
    {
        if (Input.GetKeyDown(KeyCode.Space))
        {
            points = Chaikin(points);
            SetLR(points);
        }

        if (Input.GetKeyDown(KeyCode.G))
        {
            GenerateRandomPath();
            SetLR(points);
        }
    }

    Vector3[] Chaikin(Vector3[] pts)
    {
        Vector3[] newPts = new Vector3[(pts.Length - 2) * 2 + 2];
        newPts[0] = pts[0];
        newPts[newPts.Length - 1] = pts[pts.Length - 1];

        int j = 1;
        for (int i = 0; i < pts.Length - 2; i++)
        {
            newPts[j] = pts[i] + (pts[i + 1] - pts[i]) * 0.75f;
            newPts[j + 1] = pts[i + 1] + (pts[i + 2] - pts[i + 1]) * 0.25f;
            j += 2;
        }
        return newPts;
    }
}