from multiprocessing import Pipe, Process

import cv2
import mediapipe as mp
from vpython import *

Hand tracking function

def hand_tracking(child_conn):
mp_drawing = mp.solutions.drawing_utils
mp_hands = mp.solutions.hands

cap = cv2.VideoCapture(0)

with mp_hands.Hands(
    min_detection_confidence=0.8,
    min_tracking_confidence=0.5,
    model_complexity=0,
) as hands:
    while cap.isOpened():
        ret, frame = cap.read()
        if not ret:
            break

        image = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
        image = cv2.flip(image, 1)
        image.flags.writeable = False
        results = hands.process(image)
        image.flags.writeable = True
        image = cv2.cvtColor(image, cv2.COLOR_RGB2BGR)

        if results.multi_hand_landmarks:
            for hand in results.multi_hand_landmarks:
                mp_drawing.draw_landmarks(
                    image,
                    hand,
                    mp_hands.HAND_CONNECTIONS,
                    mp_drawing.DrawingSpec(
                        color=(121, 22, 76), thickness=2, circle_radius=4
                    ),
                    mp_drawing.DrawingSpec(
                        color=(250, 44, 250), thickness=2, circle_radius=2
                    ),
                )

                thumb_tip = hand.landmark[mp_hands.HandLandmark.THUMB_TIP]
                thumb_ip = hand.landmark[mp_hands.HandLandmark.THUMB_IP]
                if thumb_ip.y < thumb_tip.y:
                    print("Thumbs up detected")
                    child_conn.send("thumbs_up")

        cv2.imshow("Hand Tracking", image)
        if cv2.waitKey(10) & 0xFF == ord("q"):
            break

cap.release()
cv2.destroyAllWindows()
child_conn.close()

VPython visualization function

def vpython_visualization(parent_conn):
vp_canvas = canvas(title=”3D Viewer”, width=1080, height=720)
box_object = box(size=vector(2, 2, 2), color=color.blue) # Create a box

if parent_conn.poll():
    gesture = parent_conn.recv()
    if gesture == "thumbs_up":
        box_object.color = color.green

while True:
    pass  
parent_conn.close()

if name == “main“:
parent_conn, child_conn = Pipe()

# Start the hand tracking process
hand_tracking_process = Process(target=hand_tracking, args=(child_conn,))
hand_tracking_process.start()

# Start the VPython visualization process
vpython_visualization_process = Process(
    target=vpython_visualization, args=(parent_conn,)
)
vpython_visualization_process.start()

# Wait for both processes to complete
hand_tracking_process.join()
vpython_visualization_process.join()

The thumbs up is detected, it should change the color of the cube but nothing happens