code from https://github.com/kenziyuliu/MS-G3D/blob/master/ntu_visualize.py

import os
import sys
import pickle
import argparse
import numpy as np
from tqdm import tqdm
import matplotlib as mpl
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
from matplotlib.animation import FuncAnimation

# NTU RGB+D 60/120 Action Classes
actions = {
    1: "drink water",
    2: "eat meal/snack",
    3: "brushing teeth",
    4: "brushing hair",
    5: "drop",
    6: "pickup",
    7: "throw",
    8: "sitting down",
    9: "standing up (from sitting position)",
    10: "clapping",
    11: "reading",
    12: "writing",
    13: "tear up paper",
    14: "wear jacket",
    15: "take off jacket",
    16: "wear a shoe",
    17: "take off a shoe",
    18: "wear on glasses",
    19: "take off glasses",
    20: "put on a hat/cap",
    21: "take off a hat/cap",
    22: "cheer up",
    23: "hand waving",
    24: "kicking something",
    25: "reach into pocket",
    26: "hopping (one foot jumping)",
    27: "jump up",
    28: "make a phone call/answer phone",
    29: "playing with phone/tablet",
    30: "typing on a keyboard",
    31: "pointing to something with finger",
    32: "taking a selfie",
    33: "check time (from watch)",
    34: "rub two hands together",
    35: "nod head/bow",
    36: "shake head",
    37: "wipe face",
    38: "salute",
    39: "put the palms together",
    40: "cross hands in front (say stop)",
    41: "sneeze/cough",
    42: "staggering",
    43: "falling",
    44: "touch head (headache)",
    45: "touch chest (stomachache/heart pain)",
    46: "touch back (backache)",
    47: "touch neck (neckache)",
    48: "nausea or vomiting condition",
    49: "use a fan (with hand or paper)/feeling warm",
    50: "punching/slapping other person",
    51: "kicking other person",
    52: "pushing other person",
    53: "pat on back of other person",
    54: "point finger at the other person",
    55: "hugging other person",
    56: "giving something to other person",
    57: "touch other person's pocket",
    58: "handshaking",
    59: "walking towards each other",
    60: "walking apart from each other",
    61: "put on headphone",
    62: "take off headphone",
    63: "shoot at the basket",
    64: "bounce ball",
    65: "tennis bat swing",
    66: "juggling table tennis balls",
    67: "hush (quite)",
    68: "flick hair",
    69: "thumb up",
    70: "thumb down",
    71: "make ok sign",
    72: "make victory sign",
    73: "staple book",
    74: "counting money",
    75: "cutting nails",
    76: "cutting paper (using scissors)",
    77: "snapping fingers",
    78: "open bottle",
    79: "sniff (smell)",
    80: "squat down",
    81: "toss a coin",
    82: "fold paper",
    83: "ball up paper",
    84: "play magic cube",
    85: "apply cream on face",
    86: "apply cream on hand back",
    87: "put on bag",
    88: "take off bag",
    89: "put something into a bag",
    90: "take something out of a bag",
    91: "open a box",
    92: "move heavy objects",
    93: "shake fist",
    94: "throw up cap/hat",
    95: "hands up (both hands)",
    96: "cross arms",
    97: "arm circles",
    98: "arm swings",
    99: "running on the spot",
    100: "butt kicks (kick backward)",
    101: "cross toe touch",
    102: "side kick",
    103: "yawn",
    104: "stretch oneself",
    105: "blow nose",
    106: "hit other person with something",
    107: "wield knife towards other person",
    108: "knock over other person (hit with body)",
    109: "grab other person’s stuff",
    110: "shoot at other person with a gun",
    111: "step on foot",
    112: "high-five",
    113: "cheers and drink",
    114: "carry something with other person",
    115: "take a photo of other person",
    116: "follow other person",
    117: "whisper in other person’s ear",
    118: "exchange things with other person",
    119: "support somebody with hand",
    120: "finger-guessing game (playing rock-paper-scissors)",
}

ntu_skeleton_bone_pairs = tuple((i - 1, j - 1) for (i, j) in (
    (1, 2), (2, 21), (3, 21), (4, 3), (5, 21), (6, 5),
    (7, 6), (8, 7), (9, 21), (10, 9), (11, 10), (12, 11),
    (13, 1), (14, 13), (15, 14), (16, 15), (17, 1), (18, 17),
    (19, 18), (20, 19), (22, 23), (21, 21), (23, 8), (24, 25), (25, 12)
))

bone_pairs = {
    'ntu/xview': ntu_skeleton_bone_pairs,
    'ntu/xsub': ntu_skeleton_bone_pairs,

    # NTU 120 uses the same skeleton structure as NTU 60
    'ntu120/xsub': ntu_skeleton_bone_pairs,
    'ntu120/xset': ntu_skeleton_bone_pairs,

    # NTU general
    'ntu': ntu_skeleton_bone_pairs,
}


def visualize(args):
    data_path = args.datapath # or './data/{}/val_data_joint.npy'.format(args.dataset)
    label_path = args.labelpath # or './data/{}/val_label.pkl.npy'.format(args.dataset)

    data = np.load(data_path, mmap_mode='r')
    with open(label_path, 'rb') as f:
        labels = pickle.load(f, encoding='latin1')

    bones = bone_pairs[args.dataset]
    print(f'Dataset: {args.dataset}\n')

    def animate(skeleton):
        ax.clear()
        ax.set_xlim([-1, 1])
        ax.set_ylim([-1, 1])
        ax.set_zlim([-1, 1])
        for i, j in bones:
            joint_locs = skeleton[:, [i, j]]
            # plot them
            ax.plot(joint_locs[0], joint_locs[1], joint_locs[2], color='blue')

        action_class = labels[1][index] + 1
        action_name = actions[action_class]
        plt.title(
            'Skeleton {} Frame #{} of 300 from {}\n (Action {}: {})'.format(index, skeleton_index[0], args.dataset,
                                                                            action_class, action_name))
        skeleton_index[0] += 1
        return ax

    for index in args.indices:
        mpl.rcParams['legend.fontsize'] = 10
        fig = plt.figure()
        ax = fig.gca(projection='3d')
        ax.set_xlim([-1, 1])
        ax.set_ylim([-1, 1])
        ax.set_zlim([-1, 1])

        # get data
        skeletons = data[index]
        action_class = labels[1][index] + 1
        action_name = actions[action_class]
        print(f'Sample index: {index}\nAction: {action_class}-{action_name}\n')  # (C,T,V,M)

        # Pick the first body to visualize
        skeleton1 = skeletons[..., 0]  # out (C,T,V)

        skeleton_index = [0]
        skeleton_frames = skeleton1.transpose(1, 0, 2)
        ani = FuncAnimation(fig, animate, skeleton_frames)

        plt.title('Skeleton {} from {} test data'.format(index, args.dataset))
        plt.show()


if __name__ == '__main__':
    # NOTE:Only supports joint data
    parser = argparse.ArgumentParser(description='NTU RGB+D Skeleton Visualizer')

    parser.add_argument('-d', '--dataset',
                        default='ntu120/xsub',
                        choices=['ntu/xview', 'ntu/xsub', 'ntu120/xset', 'ntu120/xsub'],
                        # required=True
                        )

    parser.add_argument('-p', '--datapath', default="F:\\程式碼\\NTU資料集\\data_ntu_npy\\ntu120\\xsub\\train_data_joint.npy",
                        help='location of dataset numpy file')

    parser.add_argument('-l', '--labelpath',
                        default="F:\\程式碼\\NTU資料集\\data_ntu_npy\\ntu120\\xsub\\train_label.pkl",
                        help='location of label pickle file')

    parser.add_argument('-i', '--indices',
                        type=int,
                        nargs='+',
                        default=[1],
                        # required=True,
                        help='the indices of the samples to visualize')

    args = parser.parse_args()
    visualize(args)