camera.useProjectionMatrix = true;
do3d.calculateScreenCoords(camera);
trace(do3d.screen);
//渲染后执行才可以获取


var ray:Number3D = camera.unproject(viewport.containerSprite.mouseX, viewport.containerSprite.mouseY);
ray = Number3D.add(ray, camera.position);  
//这个抽象平面和DO3D保持一致    
var plane3d:Plane3D = new Plane3D(new Number3D(0, 1, 0), new Number3D());    
var jiaodian:Number3D = plane3d.getIntersectionLineNumbers(camera.position, ray);