效果：

代码： 

<template>
  <div>
    <el-container>
      <el-main>
        <div class="box-card-left">
          <div id="threejs"></div> <div>{{ res1 }}</div> <div>{{ res2 }}</div>
        </div>
      </el-main>
    </el-container>
  </div>
</template>s
<script>
// 引入轨道控制器扩展库OrbitControls.js
import { OrbitControls } from "three/examples/jsm/controls/OrbitControls.js";
export default {
  data() {
    return {
      scene: null,
      camera: null,
      renderer: null,
      res1: null,
      res2: null,
    };
  },
  created() {},
  mounted() {
    this.name = this.$route.query.name;
    this.init();
  },
  methods: {
    goBack() {
      this.$router.go(-1);
    },
    init() {
      this.scene = new this.$three.Scene();
      const axesHelper = new this.$three.AxesHelper(100);
      this.scene.add(axesHelper);

      this.createLine();
      this.createLine2();

      this.camera = new this.$three.PerspectiveCamera(60,1,0.01,2000);
      this.camera.position.set(30,30,30);
      this.camera.lookAt(0,0,0);

      this.renderer = new this.$three.WebGLRenderer();
      this.renderer.setSize(1000,800);
      this.renderer.render(this.scene, this.camera);
      window.document.getElementById("threejs").appendChild(this.renderer.domElement);

      const controls = new OrbitControls(this.camera, this.renderer.domElement)
      controls.addEventListener("change", () => {
        this.renderer.render(this.scene, this.camera);
      })
    },
    createLine() {
      let a = new this.$three.Vector3(10,0,0);
      let b = new this.$three.Vector3(0,10,0);
      let c = new this.$three.Vector3(0,0,10);
      let geometry = new this.$three.BufferGeometry().setFromPoints([a,b,c]);
      let material = new this.$three.LineBasicMaterial({color:0xffccdd, side: this.$three.DoubleSide});
      // let line = new this.$three.LineLoop(geometry, material);
      // let line = new this.$three.Line(geometry, material);
      let line = new this.$three.Mesh(geometry, material);
      this.scene.add(line);
      this.res1 = this.createRay(a,b,c);
    },
    createLine2() {
      let arr = new Float32Array([
        20,0,0,
        0,20,0,
        0,0,20,
      ]);
      let position = new this.$three.BufferAttribute(arr, 3)
      let geometry = new this.$three.BufferGeometry();
      geometry.setAttribute("position", position);
      let material = new this.$three.LineBasicMaterial({color:0xb5a6dd});
      let line = new this.$three.LineLoop(geometry, material);
      // let line = new this.$three.Line(geometry, material);
      this.scene.add(line);
      let a = new this.$three.Vector3(20,0,0);
      let b = new this.$three.Vector3(0,20,0);
      let c = new this.$three.Vector3(0,0,20);
      this.res2 = this.createRay(a,b,c);
    },
    createRay(a,b,c) {
      // 使用箭头辅助对象显示射线的起点和方向
      let ray = new this.$three.Ray();
      ray.origin = new this.$three.Vector3(0,0,0); // 设置射线起点
      ray.direction = new this.$three.Vector3(1,1,1).normalize(); // 设置射线方向，保证方向为单位向量
      
      this.createArrowHelper(ray.direction, ray.origin);
      const point = new this.$three.Vector3();
      const result = ray.intersectTriangle(a,b,c, false, point);
      return result;
    },
    createArrowHelper(dir, origin) {
      let arrow = new this.$three.ArrowHelper(dir, origin, 20);
      this.scene.add(arrow);
    }
  },
};
</script>
<style lang="less" scoped>
.box-card-left {
  display: flex;
  align-items: flex-start;
  flex-direction: row;
  width: 100%;
  .box-right {
    img {
      width: 500px;
      user-select: none;
    }
  }
}
</style>