.. 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_examples_collision-particles.py: Collisions of particles in a box ================================ This is a simple demonstration of how you can simulate moving particles in a box using FURY. In this example, the particles collide with each other and with the walls of the container. When the collision happens between two particles, the particle with less velocity changes its color and gets the same color as the particle with higher velocity. For simplicity, in this demo we do not apply forces. .. code-block:: default import numpy as np from fury import window, actor, ui, utils import itertools Here, we define the edges of the box. .. code-block:: default def box_edges(box_lx, box_ly, box_lz): edge1 = 0.5 * np.array([[box_lx, box_ly, box_lz], [box_lx, box_ly, -box_lz], [-box_lx, box_ly, -box_lz], [-box_lx, box_ly, box_lz], [box_lx, box_ly, box_lz]]) edge2 = 0.5 * np.array([[box_lx, box_ly, box_lz], [box_lx, -box_ly, box_lz]]) edge3 = 0.5 * np.array([[box_lx, box_ly, -box_lz], [box_lx, -box_ly, -box_lz]]) edge4 = 0.5 * np.array([[-box_lx, box_ly, -box_lz], [-box_lx, -box_ly, -box_lz]]) edge5 = 0.5 * np.array([[-box_lx, box_ly, box_lz], [-box_lx, -box_ly, box_lz]]) lines = [edge1, -edge1, edge2, edge3, edge4, edge5] return lines Here we define collision between walls-particles and particle-particle. When collision happens, the particle with lower velocity gets the color of the particle with higher velocity .. code-block:: default def collision(): global xyz num_vertices = vertices.shape[0] sec = np.int(num_vertices / num_particles) for i, j in np.ndindex(num_particles, num_particles): if (i == j): continue distance = np.linalg.norm(xyz[i] - xyz[j]) vel_mag_i = np.linalg.norm(vel[i]) vel_mag_j = np.linalg.norm(vel[j]) # Collision happens if the distance between the centers of two # particles is less or equal to the sum of their radii if (distance <= (radii[i] + radii[j])): vel[i] = -vel[i] vel[j] = -vel[j] if vel_mag_j > vel_mag_i: vcolors[i * sec: i * sec + sec] = \ vcolors[j * sec: j * sec + sec] if vel_mag_i > vel_mag_j: vcolors[j * sec: j * sec + sec] = \ vcolors[i * sec: i * sec + sec] xyz[i] = xyz[i] + vel[i] * dt xyz[j] = xyz[j] + vel[j] * dt # Collision between particles-walls; vel[:, 0] = np.where(((xyz[:, 0] <= - 0.5 * box_lx + radii[:]) | (xyz[:, 0] >= (0.5 * box_lx - radii[:]))), - vel[:, 0], vel[:, 0]) vel[:, 1] = np.where(((xyz[:, 1] <= - 0.5 * box_ly + radii[:]) | (xyz[:, 1] >= (0.5 * box_ly - radii[:]))), - vel[:, 1], vel[:, 1]) vel[:, 2] = np.where(((xyz[:, 2] <= -0.5 * box_lz + radii[:]) | (xyz[:, 2] >= (0.5 * box_lz - radii[:]))), - vel[:, 2], vel[:, 2]) We define position, velocity, color and radius randomly for 50 particles inside the box. .. code-block:: default global xyz num_particles = 50 box_lx = 20 box_ly = 20 box_lz = 10 steps = 1000 dt = 0.05 xyz = np.array([box_lx, box_ly, box_lz]) * (np.random.rand(num_particles, 3) - 0.5) * 0.6 vel = 4 * (np.random.rand(num_particles, 3) - 0.5) colors = np.random.rand(num_particles, 3) radii = np.random.rand(num_particles) + 0.01 With box, streamtube and sphere actors, we can create the box, the edges of the box and the spheres respectively. .. code-block:: default scene = window.Scene() box_centers = np.array([[0, 0, 0]]) box_directions = np.array([[0, 1, 0]]) box_colors = np.array([[1, 1, 1, 0.2]]) box_actor = actor.box(box_centers, box_directions, box_colors, scales=(box_lx, box_ly, box_lz)) scene.add(box_actor) lines = box_edges(box_lx, box_ly, box_lz) line_actor = actor.streamtube(lines, colors=(1, 0.5, 0), linewidth=0.1) scene.add(line_actor) sphere_actor = actor.sphere(centers=xyz, colors=colors, radii=radii) scene.add(sphere_actor) showm = window.ShowManager(scene, size=(900, 768), reset_camera=True, order_transparent=True) showm.initialize() tb = ui.TextBlock2D(bold=True) scene.zoom(0.8) scene.azimuth(30) # use itertools to avoid global variables counter = itertools.count() vertices = utils.vertices_from_actor(sphere_actor) vcolors = utils.colors_from_actor(sphere_actor, 'colors') no_vertices_per_sphere = len(vertices)/num_particles initial_vertices = vertices.copy() - \ np.repeat(xyz, no_vertices_per_sphere, axis=0) def timer_callback(_obj, _event): global xyz cnt = next(counter) tb.message = "Let's count up to 1000 and exit :" + str(cnt) xyz = xyz + vel * dt collision() vertices[:] = initial_vertices + \ np.repeat(xyz, no_vertices_per_sphere, axis=0) utils.update_actor(sphere_actor) scene.reset_clipping_range() showm.render() if cnt == steps: showm.exit() scene.add(tb) showm.add_timer_callback(True, 50, timer_callback) interactive = False if interactive: showm.start() window.record(showm.scene, size=(900, 768), out_path="simple_collisions.png") .. image:: /auto_examples/images/sphx_glr_collision-particles_001.png :class: sphx-glr-single-img .. rst-class:: sphx-glr-timing **Total running time of the script:** ( 0 minutes 0.210 seconds) .. _sphx_glr_download_auto_examples_collision-particles.py: .. only :: html .. container:: sphx-glr-footer :class: sphx-glr-footer-example .. container:: sphx-glr-download :download:`Download Python source code: collision-particles.py ` .. container:: sphx-glr-download :download:`Download Jupyter notebook: collision-particles.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_