Three.js 剖切模型功能封裝

1.獲取到需要剖切模型的包圍盒，並計算每個包圍盒的頂點位置，代碼如下：

var Box = new THREE.Box3().setFromObject(mesh);
console.log(Box);
var point_max =new THREE.Vector3();
var point_max_right =new THREE.Vector3();
var point_max_behind =new THREE.Vector3();
var point_max_under =new THREE.Vector3();
var point_min =new THREE.Vector3();
var point_min_front =new THREE.Vector3();
var point_min_top =new THREE.Vector3();
var point_min_left =new THREE.Vector3();
point_max.set(Box.max.x,Box.max.y,Box.max.z);
point_max_right.set(Box.min.x,Box.max.y,Box.max.z);
point_max_under.set(Box.max.x,Box.max.y,Box.min.z);
point_max_behind.set(Box.max.x,Box.min.y,Box.max.z);
point_min.set(Box.min.x,Box.min.y,Box.min.z);
point_min_front.set(Box.min.x,Box.max.y,Box.min.z);
point_min_top.set(Box.min.x,Box.min.y,Box.max.z);
point_min_left.set(Box.max.x,Box.min.y,Box.min.z);

 

2.剖切面可視化，這裏以前切面爲例，別的切面以此類推，這裏的clipping_box_mesh爲全局變量。代碼如下：

//前切面可視化
var planeFront=new THREE.Geometry();
planeFront.name='front';
planeFront.vertices.push(point_max,point_max_right,point_min_front,point_max_under);
var planeFront_normal=Get_normal(point_max,point_max_under,point_min_front);
var planeFront_face1=new THREE.Face3(0,1,2, planeFront_normal);
var planeFront_face2=new THREE.Face3(2,3,0, planeFront_normal);
planeFront.faces.push(planeFront_face1,planeFront_face2);
var planeFront_material=new THREE.MeshBasicMaterial({
    color:0x00BFFF,
    side:THREE.DoubleSide,
    opacity: 0.2,
    transparent: true
});
var planeFront_mesh= new THREE.Mesh(planeFront,planeFront_material);
clipping_box_mesh.push(planeFront_mesh);
scene.add(planeFront_mesh);

3.對應可視化切面的真實切面，以前切面爲例，記得打開剖切的局部效果：

//對應前剖面
clipping_localPlane[0] = new THREE.Plane( new THREE.Vector3( 0, -1, 0 ),point_max.y );

renderer.localClippingEnabled = true; //剖切局部效果

4.綁定需要切面的mesh,以及對各個可視化切面的自身的剖切。代碼如下:

mesh.traverse(function (child) {
    if (child.isMesh)
    {
       child.material.clippingPlanes=clipping_localPlane;
        child.material.side=THREE.DoubleSide;
    }
});
for(var i=0;i<clipping_box_mesh.length;i++){
    var array_clipping=new Array();
    for(var j=0;j<clipping_box_mesh.length;j++) {
        if (i != j) {
            array_clipping.push(clipping_localPlane[j])
        }
    }
    clipping_box_mesh[i].material.clippingPlanes=array_clipping;
}

6.效果展示