neGeometry(100, 100);
		const lambert = new t3d.LambertMaterial();
		lambert.diffuse.setHex(0xf0f0f0);
		const plane = new t3d.Mesh(plane_geometry, lambert);
		plane.position.y = -10;
		scene.add(plane);

		const ambientLight = new t3d.AmbientLight(0xffffff, 0.3);
		scene.add(ambientLight);

		const directionalLight = new t3d.DirectionalLight(0xffffff, 0.6);
		directionalLight.position.set(20, 30, 40);
		directionalLight.lookAt(new t3d.Vector3(), new t3d.Vector3(0, 1, 0));
		scene.add(directionalLight);

		