.. 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_wrecking_ball.py: ======================== Wrecking Ball Simulation ======================== This example simulation shows how to use pybullet to render physics simulations in fury. In this example we specifically render a brick wall beign destroyed by a wrecking ball. First some imports. .. code-block:: default from fury import actor, window, utils, ui import numpy as np import pybullet as p import itertools Initiate pybullet and enable gravity. .. code-block:: default p.connect(p.DIRECT) p.setGravity(0, 0, -10) Define some handy parameters to customize simulation. .. code-block:: default # Parameters wall_length = 5 wall_breadth = 5 wall_height = 5 brick_size = np.array([0.2, 0.4, 0.2]) n_links = 15 dx_link = 0.1 # Size of segments link_mass = 0.5 base_mass = 0.1 radii = 0.1 ball_mass = 10 ball_radius = 0.5 ball_color = np.array([[1, 0, 0]]) joint_friction = 0.0005 Creating the base plane actor. .. code-block:: default # Base base_actor = actor.box(centers=np.array([[0, 0, 0]]), directions=[0, 0, 0], scales=(5, 5, 0.2), colors=(1, 1, 1)) base_coll = p.createCollisionShape(p.GEOM_BOX, halfExtents=[2.5, 2.5, 0.1]) base = p.createMultiBody( baseCollisionShapeIndex=base_coll, basePosition=[0, 0, -0.1], baseOrientation=[0, 0, 0, 1]) p.changeDynamics(base, -1, lateralFriction=0.3, restitution=0.5) The following definations are made to render a NxNxN brick wall. .. code-block:: default # Generate bricks. nb_bricks = wall_length*wall_breadth*wall_height 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) bricks = np.zeros(nb_bricks, dtype=np.int16) The following is the logic to position the bricks in our desired location and generate the actor. .. code-block:: default idx = 0 # Setting up wall for i in range(wall_length): for k in range(wall_height): for j in range(wall_breadth): center_pos = np.array([(i*0.2)-1.8, (j*0.4)-0.9, (0.2*k)+0.1]) brick_centers[idx] = center_pos brick_orns[idx] = np.array([0, 0, 0, 1]) bricks[idx] = p.createMultiBody(baseMass=0.5, baseCollisionShapeIndex=brick_coll, basePosition=center_pos, baseOrientation=brick_orns[i]) p.changeDynamics(bricks[idx], -1, lateralFriction=0.1, restitution=0.1) idx += 1 brick_actor = actor.box(centers=brick_centers, directions=brick_directions, scales=brick_sizes, colors=brick_colors) Now we render the wrecking ball consisting of a fixed hinge, a ball and rope. .. code-block:: default # Generate wrecking ball link_shape = p.createCollisionShape(p.GEOM_CYLINDER, radius=radii, height=dx_link, collisionFramePosition=[0, 0, -dx_link/2]) base_shape = p.createCollisionShape(p.GEOM_BOX, halfExtents=[0.01, 0.01, 0.01]) ball_shape = p.createCollisionShape(p.GEOM_SPHERE, radius=0.2) visualShapeId = -1 link_Masses = np.zeros(n_links) link_Masses[:] = link_mass link_Masses[-1] = 5 linkCollisionShapeIndices = np.zeros(n_links) linkCollisionShapeIndices[:] = np.array(link_shape) linkCollisionShapeIndices[-1] = ball_shape linkVisualShapeIndices = -1 * np.ones(n_links) linkPositions = np.zeros((n_links, 3)) linkPositions[:] = np.array([0, 0, -dx_link]) linkOrientations = np.zeros((n_links, 4)) linkOrientations[:] = np.array([0, 0, 0, 1]) linkInertialFramePositions = np.zeros((n_links, 3)) linkInertialFrameOrns = np.zeros((n_links, 4)) linkInertialFrameOrns[:] = np.array([0, 0, 0, 1]) indices = np.arange(n_links) jointTypes = np.zeros(n_links) jointTypes[:] = np.array(p.JOINT_SPHERICAL) axis = np.zeros((n_links, 3)) axis[:] = np.array([1, 0, 0]) linkDirections = np.zeros((n_links, 3)) linkDirections[:] = np.array([1, 1, 1]) link_radii = np.zeros(n_links) link_radii[:] = radii link_heights = np.zeros(n_links) link_heights[:] = dx_link rope_actor = actor.cylinder(centers=linkPositions, directions=linkDirections, colors=np.random.rand(n_links, 3), radius=radii, heights=link_heights, capped=True) basePosition = [0, 0, 2] baseOrientation = [0, 0, 0, 1] rope = p.createMultiBody(base_mass, base_shape, visualShapeId, basePosition, baseOrientation, linkMasses=link_Masses, linkCollisionShapeIndices=linkCollisionShapeIndices, linkVisualShapeIndices=linkVisualShapeIndices, linkPositions=linkPositions, linkOrientations=linkOrientations, linkInertialFramePositions=linkInertialFramePositions, linkInertialFrameOrientations=linkInertialFrameOrns, linkParentIndices=indices, linkJointTypes=jointTypes, linkJointAxis=axis) Next we define the frictional force between the joints of wrecking ball. .. code-block:: default friction_vec = [joint_friction]*3 # same all axis control_mode = p.POSITION_CONTROL # set pos control mode for j in range(p.getNumJoints(rope)): p.setJointMotorControlMultiDof(rope, j, control_mode, targetPosition=[0, 0, 0, 1], targetVelocity=[0, 0, 0], positionGain=0, velocityGain=1, force=friction_vec) We add the following constraint to keep the cubical hinge fixed. .. code-block:: default root_robe_c = p.createConstraint(rope, -1, -1, -1, p.JOINT_FIXED, [0, 0, 0], [0, 0, 0], [0, 0, 2]) box_actor = actor.box(centers=np.array([[0, 0, 0]]), directions=np.array([[0, 0, 0]]), scales=(0.02, 0.02, 0.02), colors=np.array([[1, 0, 0]])) ball_actor = actor.sphere(centers=np.array([[0, 0, 0]]), radii=0.2, colors=np.array([1, 0, 1])) Now we add the necessary actors to the scene and set the camera for better visualization. .. code-block:: default scene = window.Scene() scene.set_camera((10.28, -7.10, 6.39), (0.0, 0.0, 0.4), (-0.35, 0.26, 1.0)) scene.add(actor.axes(scale=(0.5, 0.5, 0.5)), base_actor, brick_actor) scene.add(rope_actor, box_actor, ball_actor) showm = window.ShowManager(scene, size=(900, 768), reset_camera=False, order_transparent=True) showm.initialize() Position the base correctly. .. code-block:: default base_pos, base_orn = p.getBasePositionAndOrientation(base) base_actor.SetPosition(*base_pos) Calculate the vertices of the bricks. .. code-block:: default brick_vertices = utils.vertices_from_actor(brick_actor) num_vertices = brick_vertices.shape[0] num_objects = brick_centers.shape[0] brick_sec = np.int(num_vertices / num_objects) Calculate the vertices of the wrecking ball. .. code-block:: default chain_vertices = utils.vertices_from_actor(rope_actor) num_vertices = chain_vertices.shape[0] num_objects = brick_centers.shape[0] chain_sec = np.int(num_vertices / num_objects) We define methods to sync bricks and wrecking ball. .. code-block:: default # Function for syncing actors with multibodies. 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)) sec = brick_sec brick_vertices[object_index * sec: object_index * sec + sec] = \ (brick_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 def sync_chain(actor_list, multibody): for joint in range(p.getNumJoints(multibody)): # `p.getLinkState` offers various information about the joints # as a list and the values in 4th and 5th index refer to the joint's # position and orientation respectively. pos, orn = p.getLinkState(multibody, joint)[4:6] rot_mat = np.reshape( p.getMatrixFromQuaternion( p.getDifferenceQuaternion(orn, linkOrientations[joint])), (3, 3)) sec = chain_sec chain_vertices[joint * sec: joint * sec + sec] =\ (chain_vertices[joint * sec: joint * sec + sec] - linkPositions[joint])@rot_mat + pos linkPositions[joint] = pos linkOrientations[joint] = orn Some helper tools to keep track of avg. FPS and simulation steps. .. code-block:: default counter = itertools.count() fpss = np.array([]) tb = ui.TextBlock2D(position=(0, 680), font_size=30, color=(1, 0.5, 0), text="Avg. FPS: \nSim Steps: ") scene.add(tb) Timer callback to sync objects, simulate steps and apply force. .. code-block:: default apply_force = True # 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) # Updating the position and orientation of each individual brick. for idx, brick in enumerate(bricks): sync_brick(idx, brick) pos, _ = p.getBasePositionAndOrientation(rope) if apply_force: p.applyExternalForce(rope, -1, forceObj=[-500, 0, 0], posObj=pos, flags=p.WORLD_FRAME) apply_force = False pos = p.getLinkState(rope, p.getNumJoints(rope)-1)[4] ball_actor.SetPosition(*pos) sync_chain(rope_actor, rope) utils.update_actor(brick_actor) utils.update_actor(rope_actor) # Simulate a step. p.stepSimulation() 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, size=(900, 768), out_path="viz_wrecking_ball.png") .. image:: /auto_tutorials/05_physics/images/sphx_glr_viz_wrecking_ball_001.png :class: sphx-glr-single-img .. rst-class:: sphx-glr-timing **Total running time of the script:** ( 0 minutes 0.244 seconds) .. _sphx_glr_download_auto_tutorials_05_physics_viz_wrecking_ball.py: .. only :: html .. container:: sphx-glr-footer :class: sphx-glr-footer-example .. container:: sphx-glr-download :download:`Download Python source code: viz_wrecking_ball.py ` .. container:: sphx-glr-download :download:`Download Jupyter notebook: viz_wrecking_ball.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_