.. note:: :class: sphx-glr-download-link-note Click :ref:`here ` to download the full example code .. rst-class:: sphx-glr-example-title .. _sphx_glr_auto_tutorials_05_physics_viz_brick_wall.py: ===================== Brick Wall Simulation ===================== This example simulation shows how to use pybullet to render physics simulations in fury. In this example we specifically render a ball beign thrown at a brick wall. First some imports. .. code-block:: default import numpy as np from fury import window, actor, ui, utils import itertools import pybullet as p Next, we initialize a pybullet client to render the physics. We use `DIRECT` mode to initialize pybullet without a GUI. .. code-block:: default p.connect(p.DIRECT) Apply gravity to the scene. In pybullet all values are in SI units. .. code-block:: default p.setGravity(0, 0, -10) We define some global parameters so that its easier for us to tweak the tweak the simulation. .. code-block:: default # Ball Parameters ball_radius = 0.3 ball_color = np.array([1, 0, 0]) ball_mass = 3 ball_position = np.array([2, 0, 1.5]) ball_orientation = np.array([0, 0, 0, 1]) # Base Plane Parameters base_size = np.array([5, 5, 0.2]) base_color = np.array([1, 1, 1]) base_position = np.array([0, 0, -0.1]) base_orientation = np.array([0, 0, 0, 1]) # Wall Parameters wall_height = 10 wall_width = 10 brick_mass = 0.5 brick_size = np.array([0.2, 0.4, 0.2]) Now we define the required parameters to render the Ball. .. code-block:: default # Ball actor ball_actor = actor.sphere(centers=np.array([[0, 0, 0]]), colors=ball_color, radii=ball_radius) # Collision shape for the ball. ball_coll = p.createCollisionShape(p.GEOM_SPHERE, radius=ball_radius) # Creating a Multibody which will be tracked by pybullet. ball = p.createMultiBody(baseMass=3, baseCollisionShapeIndex=ball_coll, basePosition=ball_position, baseOrientation=ball_orientation) # Change the dynamics of the ball by adding friction and restitution. p.changeDynamics(ball, -1, lateralFriction=0.3, restitution=0.5) Render a base plane to support the bricks. .. code-block:: default base_actor = actor.box(centers=np.array([[0, 0, 0]]), directions=[0, 0, 0], scales=base_size, colors=base_color) base_coll = p.createCollisionShape(p.GEOM_BOX, halfExtents=base_size/2) # half of the actual size. base = p.createMultiBody( baseCollisionShapeIndex=base_coll, basePosition=base_position, baseOrientation=base_orientation) p.changeDynamics(base, -1, lateralFriction=0.3, restitution=0.5) Now we render the bricks. All the bricks are rendered by a single actor for better performance. .. code-block:: default nb_bricks = wall_height*wall_width brick_centers = np.zeros((nb_bricks, 3)) brick_directions = np.zeros((nb_bricks, 3)) brick_directions[:] = np.array([1.57, 0, 0]) brick_orns = np.zeros((nb_bricks, 4)) brick_sizes = np.zeros((nb_bricks, 3)) brick_sizes[:] = brick_size brick_colors = np.random.rand(nb_bricks, 3) brick_coll = p.createCollisionShape(p.GEOM_BOX, halfExtents=brick_size/2) # We use this array to store the reference of brick objects in pybullet world. bricks = np.zeros(nb_bricks, dtype=np.int8) # Logic to position the bricks appropriately to form a wall. i = 0 for k in range(wall_height): for j in range(wall_width): center_pos = np.array([-1, (j*0.4)-1.8, (0.2*k)+0.1]) brick_centers[i] = center_pos brick_orns[i] = np.array([0, 0, 0, 1]) bricks[i] = p.createMultiBody(baseMass=brick_mass, baseCollisionShapeIndex=brick_coll, basePosition=center_pos, baseOrientation=brick_orns[i]) p.changeDynamics(bricks[i], -1, lateralFriction=0.1, restitution=0.1) i += 1 brick_actor = actor.box(centers=brick_centers, directions=brick_directions, scales=brick_sizes, colors=brick_colors) Now, we define a scene and add actors to it. .. code-block:: default scene = window.Scene() scene.add(actor.axes()) scene.add(ball_actor) scene.add(base_actor) scene.add(brick_actor) # Create show manager. showm = window.ShowManager(scene, size=(900, 768), reset_camera=False, order_transparent=True) showm.initialize() # Counter interator for tracking simulation steps. counter = itertools.count() # Variable for tracking applied force. apply_force = True Now, we define methods to sync objects between fury and Pybullet. .. code-block:: default # Get the position of base and set it. base_pos, _ = p.getBasePositionAndOrientation(base) base_actor.SetPosition(*base_pos) # Do the same for ball. ball_pos, _ = p.getBasePositionAndOrientation(ball) ball_actor.SetPosition(*ball_pos) # Calculate the vertices of the bricks. vertices = utils.vertices_from_actor(brick_actor) num_vertices = vertices.shape[0] num_objects = brick_centers.shape[0] sec = np.int(num_vertices / num_objects) ============== Syncing Bricks ============== Here, we perform three major steps to sync bricks accurately. * Get the position and orientation of the bricks from pybullet. * Calculate the Rotation Matrix. * Get the difference in orientations (Quaternion). * Generate the corresponding rotation matrix according to that difference. * Reshape it in a 3x3 matrix. * Perform calculations to get the required position and orientation. * Update the position and orientation. .. code-block:: default def sync_brick(object_index, multibody): pos, orn = p.getBasePositionAndOrientation(multibody) rot_mat = np.reshape( p.getMatrixFromQuaternion( p.getDifferenceQuaternion(orn, brick_orns[object_index])), (3, 3)) vertices[object_index * sec: object_index * sec + sec] = \ (vertices[object_index * sec: object_index * sec + sec] - brick_centers[object_index])@rot_mat + pos brick_centers[object_index] = pos brick_orns[object_index] = orn A simpler but inaccurate approach is used here to update the position and orientation. .. code-block:: default def sync_actor(actor, multibody): pos, orn = p.getBasePositionAndOrientation(multibody) actor.SetPosition(*pos) orn_deg = np.degrees(p.getEulerFromQuaternion(orn)) actor.SetOrientation(*orn_deg) Here, we define a textblock to display the Avg. FPS and simulation steps. .. code-block:: default fpss = np.array([]) tb = ui.TextBlock2D(text="Avg. FPS: \nSim Steps: ", position=(0, 680), font_size=30, color=(1, 0.5, 0)) scene.add(tb) Set the camera for better visualization. .. code-block:: default scene.set_camera(position=(10.46, -8.13, 6.18), focal_point=(0.0, 0.0, 0.79), view_up=(-0.27, 0.26, 0.90)) Timer callback is created which is responsible for calling the sync and simulation methods. .. code-block:: default # Create timer callback which will execute at each step of simulation. def timer_callback(_obj, _event): global apply_force, fpss cnt = next(counter) showm.render() if cnt % 1 == 0: fps = scene.frame_rate fpss = np.append(fpss, fps) tb.message = "Avg. FPS: " + str(np.round(np.mean(fpss), 0)) +\ "\nSim Steps: " + str(cnt) # Get the position and orientation of the ball. ball_pos, ball_orn = p.getBasePositionAndOrientation(ball) # Apply force for 5 times for the first step of simulation. if apply_force: # Apply the force. p.applyExternalForce(ball, -1, forceObj=[-10000, 0, 0], posObj=ball_pos, flags=p.WORLD_FRAME) apply_force = False # Set position and orientation of the ball. sync_actor(ball_actor, ball) # Updating the position and orientation of each individual brick. for idx, brick in enumerate(bricks): sync_brick(idx, brick) utils.update_actor(brick_actor) # Simulate a step. p.stepSimulation() # Exit after 2000 steps of simulation. if cnt == 130: showm.exit() # Add the timer callback to showmanager. # Increasing the duration value will slow down the simulation. showm.add_timer_callback(True, 1, timer_callback) interactive = False # start simulation if interactive: showm.start() window.record(scene, out_path="viz_brick_wall.png", size=(900, 768)) .. image:: /auto_tutorials/05_physics/images/sphx_glr_viz_brick_wall_001.png :class: sphx-glr-single-img .. rst-class:: sphx-glr-timing **Total running time of the script:** ( 0 minutes 0.239 seconds) .. _sphx_glr_download_auto_tutorials_05_physics_viz_brick_wall.py: .. only :: html .. container:: sphx-glr-footer :class: sphx-glr-footer-example .. container:: sphx-glr-download :download:`Download Python source code: viz_brick_wall.py ` .. container:: sphx-glr-download :download:`Download Jupyter notebook: viz_brick_wall.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_