How to use the pyrender.Node function in pyrender

axis_orthogonal = fig.add_subplot(1, 2, 2)
    ims = []

    scene = build_scene(
        floor_textures,
        wall_textures,
        fix_light_position=args.fix_light_position)
    place_dice(
        scene,
        mnist_images,
        discrete_position=args.discrete_position,
        rotate_dice=args.rotate_dice)

    camera_distance = 5
    perspective_camera = PerspectiveCamera(yfov=math.pi / 4)
    perspective_camera_node = Node(
        camera=perspective_camera, translation=np.array([0, 1, 1]))
    orthographic_camera = OrthographicCamera(xmag=3, ymag=3)
    orthographic_camera_node = Node(camera=orthographic_camera)

    rad_step = math.pi / 36
    total_frames = int(math.pi * 2 / rad_step)
    current_rad = 0
    for _ in range(total_frames):
        scene.add_node(perspective_camera_node)

        # Perspective camera
        camera_xz = camera_distance * np.array(
            (math.sin(current_rad), math.cos(current_rad)))
        # Compute yaw and pitch
        camera_direction = np.array([camera_xz[0], 0, camera_xz[1]])
        yaw, pitch = compute_yaw_and_pitch(camera_direction)

def build_scene(floor_textures, wall_textures, fix_light_position=False):
    scene = Scene(
        bg_color=np.array([153 / 255, 226 / 255, 249 / 255]),
        ambient_light=np.array([0.5, 0.5, 0.5, 1.0]))

    floor_trimesh = trimesh.load("{}/floor.obj".format(object_directory))
    mesh = Mesh.from_trimesh(floor_trimesh, smooth=False)
    node = Node(
        mesh=mesh,
        rotation=pyrender.quaternion.from_pitch(-math.pi / 2),
        translation=np.array([0, 0, 0]))
    texture_path = random.choice(floor_textures)
    set_random_texture(node, texture_path)
    scene.add_node(node)

    texture_path = random.choice(wall_textures)

    wall_trimesh = trimesh.load("{}/wall.obj".format(object_directory))
    mesh = Mesh.from_trimesh(wall_trimesh, smooth=False)
    node = Node(mesh=mesh, translation=np.array([0, 1.15, -3.5]))
    set_random_texture(node, texture_path)
    scene.add_node(node)

    mesh = Mesh.from_trimesh(wall_trimesh, smooth=False)

# Place objects
    directions = [-1.0, 0.0, 1.0]
    available_positions = []
    for z in directions:
        for x in directions:
            available_positions.append((x, z))
    available_positions = np.array(available_positions)
    num_objects = random.choice(range(args.max_num_objects)) + 1
    indices = np.random.choice(
        np.arange(len(available_positions)), replace=False, size=num_objects)
    for xz in available_positions[indices]:
        node = random.choice(objects)()
        node.mesh.primitives[0].color_0 = random.choice(colors)
        if args.discrete_position == False:
            xz += np.random.uniform(-0.25, 0.25, size=xz.shape)
        parent = Node(children=[node], translation=np.array([xz[0], 0, xz[1]]))
        scene.add_node(parent)

    return scene

fix_light_position=args.fix_light_position)
    place_objects(
        scene,
        colors,
        objects,
        min_num_objects=args.num_objects,
        max_num_objects=args.num_objects,
        discrete_position=args.discrete_position,
        rotate_object=args.rotate_object)

    camera_distance = 5
    perspective_camera = PerspectiveCamera(yfov=math.pi / 4)
    perspective_camera_node = Node(
        camera=perspective_camera, translation=np.array([0, 1, 1]))
    orthographic_camera = OrthographicCamera(xmag=3, ymag=3)
    orthographic_camera_node = Node(camera=orthographic_camera)

    rad_step = math.pi / 36
    total_frames = int(math.pi * 2 / rad_step)
    current_rad = 0
    for _ in range(total_frames):
        scene.add_node(perspective_camera_node)

        # Perspective camera
        camera_xz = camera_distance * np.array(
            (math.sin(current_rad), math.cos(current_rad)))
        # Compute yaw and pitch
        camera_direction = np.array([camera_xz[0], 0, camera_xz[1]])
        yaw, pitch = compute_yaw_and_pitch(camera_direction)

        perspective_camera_node.rotation = genearte_camera_quaternion(
            yaw, pitch)

mesh=mesh,
        rotation=pyrender.quaternion.from_yaw(math.pi),
        translation=np.array([0, 1.15, 3.5]))
    set_random_texture(node, texture_path)
    scene.add_node(node)

    mesh = Mesh.from_trimesh(wall_trimesh, smooth=False)
    node = Node(
        mesh=mesh,
        rotation=pyrender.quaternion.from_yaw(-math.pi / 2),
        translation=np.array([3.5, 1.15, 0]))
    set_random_texture(node, texture_path)
    scene.add_node(node)

    mesh = Mesh.from_trimesh(wall_trimesh, smooth=False)
    node = Node(
        mesh=mesh,
        rotation=pyrender.quaternion.from_yaw(math.pi / 2),
        translation=np.array([-3.5, 1.15, 0]))
    set_random_texture(node, texture_path)
    scene.add_node(node)

    light = DirectionalLight(color=np.ones(3), intensity=10)
    if fix_light_position == True:
        translation = np.array([1, 1, 1])
    else:
        xz = np.random.uniform(-1, 1, size=2)
        translation = np.array([xz[0], 1, xz[1]])
    yaw, pitch = compute_yaw_and_pitch(translation)
    node = Node(
        light=light,
        rotation=genearte_camera_quaternion(yaw, pitch),

floor_trimesh = trimesh.load("objects/floor.obj")
    mesh = Mesh.from_trimesh(floor_trimesh)
    node = Node(
        mesh=mesh,
        rotation=pyrender.quaternion.from_pitch(-math.pi / 2),
        translation=np.array([0, 0, 0]))
    texture_path = random.choice(floor_textures)
    set_random_texture(node, texture_path, intensity=0.8)
    scene.add_node(node)

    texture_path = random.choice(wall_textures)

    wall_trimesh = trimesh.load("objects/wall.obj")
    mesh = Mesh.from_trimesh(wall_trimesh)
    node = Node(mesh=mesh, translation=np.array([0, 1.15, -3.5]))
    set_random_texture(node, texture_path)
    scene.add_node(node)

    mesh = Mesh.from_trimesh(wall_trimesh)
    node = Node(
        mesh=mesh,
        rotation=pyrender.quaternion.from_yaw(math.pi),
        translation=np.array([0, 1.15, 3.5]))
    set_random_texture(node, texture_path)
    scene.add_node(node)

    mesh = Mesh.from_trimesh(wall_trimesh)
    node = Node(
        mesh=mesh,
        rotation=pyrender.quaternion.from_yaw(-math.pi / 2),
        translation=np.array([3.5, 1.15, 0]))

for scene_index in tqdm(range(total_scenes_to_render)):
        scene = build_scene(
            floor_textures,
            wall_textures,
            fix_light_position=args.fix_light_position)
        place_objects(
            scene,
            colors,
            objects,
            max_num_objects=args.max_num_objects,
            discrete_position=args.discrete_position,
            rotate_object=args.rotate_object)
        camera_distance = 4.5
        camera = PerspectiveCamera(yfov=math.pi / 4)
        camera_node = Node(camera=camera, translation=np.array([0, 1, 1]))
        scene.add_node(camera_node)
        scene_data = SceneData((args.image_size, args.image_size),
                               args.num_observations_per_scene)
        for observation_index in range(args.num_observations_per_scene):
            rand_position_xz = np.random.normal(size=2)
            rand_position_xz = camera_distance * rand_position_xz / np.linalg.norm(
                rand_position_xz)
            # Compute yaw and pitch
            camera_direction = np.array(
                [rand_position_xz[0], 0, rand_position_xz[1]])
            yaw, pitch = compute_yaw_and_pitch(camera_direction)

            camera_node.rotation = genearte_camera_quaternion(yaw, pitch)
            camera_position = np.array(
                [rand_position_xz[0], 1, rand_position_xz[1]])
            camera_node.translation = camera_position

def Box():
    sphere = trimesh.creation.box(extents=np.array([0.5, 0.5, 0.5]))
    mesh = Mesh.from_trimesh(sphere, smooth=False)
    node = Node(mesh=mesh, translation=np.array([0, 0.25, 0]))
    return node

rotation=pyrender.quaternion.from_yaw(math.pi / 2),
        translation=np.array([-3.5, 1.15, 0]))
    set_random_texture(node, texture_path)
    scene.add_node(node)

    # light = PointLight(color=np.ones(3), intensity=200.0)
    # node = Node(
    #     light=light,
    #     translation=np.array([0, 5, 5]))
    # scene.add_node(node)

    light = DirectionalLight(color=np.ones(3), intensity=10)
    position = np.array([0, 1, 1])
    position = position / np.linalg.norm(position)
    yaw, pitch = compute_yaw_and_pitch(position)
    node = Node(
        light=light,
        rotation=genearte_camera_quaternion(yaw, pitch),
        translation=np.array([0, 1, 1]))
    scene.add_node(node)

    # Place objects
    directions = [-1.0, 0.0, 1.0]
    available_positions = []
    for z in directions:
        for x in directions:
            available_positions.append((x, z))
    available_positions = np.array(available_positions)
    num_objects = random.choice(range(args.max_num_objects)) + 1
    indices = np.random.choice(
        np.arange(len(available_positions)), replace=False, size=num_objects)
    for xz in available_positions[indices]:

#==============================================================================

scene = Scene(ambient_light=np.array([0.02, 0.02, 0.02, 1.0]))

#==============================================================================
# Adding objects to the scene
#==============================================================================

#------------------------------------------------------------------------------
# By manually creating nodes
#------------------------------------------------------------------------------
fuze_node = Node(mesh=fuze_mesh, translation=np.array([0.1, 0.15, -np.min(fuze_trimesh.vertices[:,2])]))
scene.add_node(fuze_node)
boxv_node = Node(mesh=boxv_mesh, translation=np.array([-0.1, 0.10, 0.05]))
scene.add_node(boxv_node)
boxf_node = Node(mesh=boxf_mesh, translation=np.array([-0.1, -0.10, 0.05]))
scene.add_node(boxf_node)

#------------------------------------------------------------------------------
# By using the add() utility function
#------------------------------------------------------------------------------
drill_node = scene.add(drill_mesh, pose=drill_pose)
bottle_node = scene.add(bottle_mesh, pose=bottle_pose)
wood_node = scene.add(wood_mesh)
direc_l_node = scene.add(direc_l, pose=cam_pose)
spot_l_node = scene.add(spot_l, pose=cam_pose)

#==============================================================================
# Using the viewer with a default camera
#==============================================================================

v = Viewer(scene, shadows=True)