开发环境：Unity 2022.3.5f1c1 + Visual Studio 2022
太阳系相关星体：太阳、八大行星、月球
模拟星系：太阳系、地月系
功能：支持行星以太阳为中心，任意轴进行公转，此处演示同一平面。
a1-a8为公转轴，可以任意修改，InitStarPosition()将会修正星体初始位置；MoveAroundSun脚本挂在SolarSystemGroup对象上（空对象）。
动态演示效果

静态展示图片

核心代码

using UnityEngine;public class MoveAroundSun : MonoBehaviour
{// 星体public Transform Sun;public Transform Mercury;public Transform Venus;public Transform Earth;public Transform Moon;public Transform Mars;public Transform Jupiter;public Transform Saturn;public Transform Uranus;public Transform Neptune;// 公转轴：Mercury至Neptune八大行星Vector3 a1 = new Vector3(0, 1, 0);Vector3 a2 = new Vector3(0, 1, 0);Vector3 a3 = new Vector3(0, 1, 0);Vector3 a4 = new Vector3(0, 1, 0);Vector3 a5 = new Vector3(0, 1, 0);Vector3 a6 = new Vector3(0, 1, 0);Vector3 a7 = new Vector3(0, 1, 0);Vector3 a8 = new Vector3(0, 1, 0);/// <summary>/// 初始化行星位置，使Star位于以Center为中心，rotateAxis为公转轴的法平面上/// </summary>/// <param name="center">公转中心</param>/// <param name="star">公转行星</param>/// <param name="rotateAxis">公转轴</param>void InitStarPosition(Vector3 center, Transform star, Vector3 rotateAxis){// 中心点指向行星的方向向量Vector3 centerToStar = star.position - center;// 通过方向向量和公转轴向量的叉乘，得到这两个向量所在平面的法向量Vector3 normal = Vector3.Cross(rotateAxis, centerToStar);// 计算方向向量和公转轴向量的角度float angle = Vector3.Angle(rotateAxis, centerToStar);// 计算方向向量转动到法向量的角度（转动到法平面上的角度）float rotateAngle = Mathf.Abs(90 - angle);// 以太阳为中心，法向量为转轴来转动角度star.RotateAround(center, normal, rotateAngle);}// Start is called before the first frame updatevoid Start(){// 为了让任意位置的星体都可以绕任意轴旋转，需要在初始时刻定位星体位置（只挂载一个脚本，所以有重复代码）InitStarPosition(Sun.position, Mercury, a1);InitStarPosition(Sun.position, Venus, a2);InitStarPosition(Sun.position, Earth, a3);InitStarPosition(Sun.position, Mars, a4);InitStarPosition(Sun.position, Jupiter, a5);InitStarPosition(Sun.position, Saturn, a6);InitStarPosition(Sun.position, Uranus, a7);InitStarPosition(Sun.position, Neptune, a8);InitStarPosition(Earth.position, Moon, Earth.transform.up);}// Update is called once per framevoid Update(){Mercury.RotateAround(Sun.position, a1, 20 * Time.deltaTime);Mercury.Rotate(Vector3.up * 50 * Time.deltaTime);Venus.RotateAround(Sun.position, a2, 10 * Time.deltaTime);Venus.Rotate(Vector3.up * 30 * Time.deltaTime);Earth.RotateAround(Sun.position, a3, 10 * Time.deltaTime);Earth.Rotate(Vector3.up * 30 * Time.deltaTime);Moon.transform.RotateAround(Earth.position, Vector3.up, 359 * Time.deltaTime);Mars.RotateAround(Sun.position, a4, 8 * Time.deltaTime);Mars.Rotate(Vector3.up * 30 * Time.deltaTime);Jupiter.RotateAround(Sun.position, a5, 7 * Time.deltaTime);Jupiter.Rotate(Vector3.up * 30 * Time.deltaTime);Saturn.RotateAround(Sun.position, a6, 6 * Time.deltaTime);Saturn.Rotate(Vector3.up * 30 * Time.deltaTime);Uranus.RotateAround(Sun.position, a7, 5 * Time.deltaTime);Uranus.Rotate(Vector3.up * 30 * Time.deltaTime);Neptune.RotateAround(Sun.position, a8, 4 * Time.deltaTime);Neptune.Rotate(Vector3.up * 30 * Time.deltaTime);}
}