############### Example Gallery ############### This gallery contains a collection of best practice code snippets together with their corresponding video/image output, illustrating different functionalities all across the library. These are all under the MIT license, so feel free to copy & paste them to your projects. Enjoy this taste of Manim! .. tip:: This gallery is not the only place in our documentation where you can see explicit code and video examples: there are many more in our :doc:`reference manual ` -- see, for example, our documentation for the modules :mod:`~.tex_mobject`, :mod:`~.geometry`, :mod:`~.moving_camera_scene`, and many more. Check out our `interactive Jupyter environment `_ which allows running the examples online, without requiring a local installation. Also, visit our `Twitter `_ for more *manimations*! Basic Concepts ============== .. manim:: ManimCELogo :save_last_frame: :ref_classes: MathTex Circle Square Triangle class ManimCELogo(Scene): def construct(self): self.camera.background_color = "#ece6e2" logo_green = "#87c2a5" logo_blue = "#525893" logo_red = "#e07a5f" logo_black = "#343434" ds_m = MathTex(r"\mathbb{M}", fill_color=logo_black).scale(7) ds_m.shift(2.25 * LEFT + 1.5 * UP) circle = Circle(color=logo_green, fill_opacity=1).shift(LEFT) square = Square(color=logo_blue, fill_opacity=1).shift(UP) triangle = Triangle(color=logo_red, fill_opacity=1).shift(RIGHT) logo = VGroup(triangle, square, circle, ds_m) # order matters logo.move_to(ORIGIN) self.add(logo) .. manim:: BraceAnnotation :save_last_frame: :ref_classes: Brace :ref_methods: Brace.get_text Brace.get_tex class BraceAnnotation(Scene): def construct(self): dot = Dot([-2, -1, 0]) dot2 = Dot([2, 1, 0]) line = Line(dot.get_center(), dot2.get_center()).set_color(ORANGE) b1 = Brace(line) b1text = b1.get_text("Horizontal distance") b2 = Brace(line, direction=line.copy().rotate(PI / 2).get_unit_vector()) b2text = b2.get_tex("x-x_1") self.add(line, dot, dot2, b1, b2, b1text, b2text) .. manim:: VectorArrow :save_last_frame: :ref_classes: Dot Arrow NumberPlane Text class VectorArrow(Scene): def construct(self): dot = Dot(ORIGIN) arrow = Arrow(ORIGIN, [2, 2, 0], buff=0) numberplane = NumberPlane() origin_text = Text('(0, 0)').next_to(dot, DOWN) tip_text = Text('(2, 2)').next_to(arrow.get_end(), RIGHT) self.add(numberplane, dot, arrow, origin_text, tip_text) .. manim:: GradientImageFromArray :save_last_frame: :ref_classes: ImageMobject class GradientImageFromArray(Scene): def construct(self): n = 256 imageArray = np.uint8( [[i * 256 / n for i in range(0, n)] for _ in range(0, n)] ) image = ImageMobject(imageArray).scale(2) image.background_rectangle = SurroundingRectangle(image, GREEN) self.add(image, image.background_rectangle) .. manim:: BooleanOperations :ref_classes: Union Intersection Exclusion class BooleanOperations(Scene): def construct(self): ellipse1 = Ellipse( width=4.0, height=5.0, fill_opacity=0.5, color=BLUE, stroke_width=10 ).move_to(LEFT) ellipse2 = ellipse1.copy().set_color(color=RED).move_to(RIGHT) bool_ops_text = MarkupText("Boolean Operation").next_to(ellipse1, UP * 3) ellipse_group = Group(bool_ops_text, ellipse1, ellipse2).move_to(LEFT * 3) self.play(FadeIn(ellipse_group)) i = Intersection(ellipse1, ellipse2, color=GREEN, fill_opacity=0.5) self.play(i.animate.scale(0.25).move_to(RIGHT * 5 + UP * 2.5)) intersection_text = Text("Intersection", font_size=23).next_to(i, UP) self.play(FadeIn(intersection_text)) u = Union(ellipse1, ellipse2, color=ORANGE, fill_opacity=0.5) union_text = Text("Union", font_size=23) self.play(u.animate.scale(0.3).next_to(i, DOWN, buff=union_text.height * 3)) union_text.next_to(u, UP) self.play(FadeIn(union_text)) e = Exclusion(ellipse1, ellipse2, color=YELLOW, fill_opacity=0.5) exclusion_text = Text("Exclusion", font_size=23) self.play(e.animate.scale(0.3).next_to(u, DOWN, buff=exclusion_text.height * 3.5)) exclusion_text.next_to(e, UP) self.play(FadeIn(exclusion_text)) d = Difference(ellipse1, ellipse2, color=PINK, fill_opacity=0.5) difference_text = Text("Difference", font_size=23) self.play(d.animate.scale(0.3).next_to(u, LEFT, buff=difference_text.height * 3.5)) difference_text.next_to(d, UP) self.play(FadeIn(difference_text)) Animations ========== .. manim:: PointMovingOnShapes :ref_classes: Circle Dot Line GrowFromCenter Transform MoveAlongPath Rotating class PointMovingOnShapes(Scene): def construct(self): circle = Circle(radius=1, color=BLUE) dot = Dot() dot2 = dot.copy().shift(RIGHT) self.add(dot) line = Line([3, 0, 0], [5, 0, 0]) self.add(line) self.play(GrowFromCenter(circle)) self.play(Transform(dot, dot2)) self.play(MoveAlongPath(dot, circle), run_time=2, rate_func=linear) self.play(Rotating(dot, about_point=[2, 0, 0]), run_time=1.5) self.wait() .. manim:: MovingAround :ref_methods: Mobject.shift VMobject.set_fill Mobject.scale Mobject.rotate class MovingAround(Scene): def construct(self): square = Square(color=BLUE, fill_opacity=1) self.play(square.animate.shift(LEFT)) self.play(square.animate.set_fill(ORANGE)) self.play(square.animate.scale(0.3)) self.play(square.animate.rotate(0.4)) .. manim:: MovingAngle :ref_classes: Angle :ref_methods: Mobject.rotate class MovingAngle(Scene): def construct(self): rotation_center = LEFT theta_tracker = ValueTracker(110) line1 = Line(LEFT, RIGHT) line_moving = Line(LEFT, RIGHT) line_ref = line_moving.copy() line_moving.rotate( theta_tracker.get_value() * DEGREES, about_point=rotation_center ) a = Angle(line1, line_moving, radius=0.5, other_angle=False) tex = MathTex(r"\theta").move_to( Angle( line1, line_moving, radius=0.5 + 3 * SMALL_BUFF, other_angle=False ).point_from_proportion(0.5) ) self.add(line1, line_moving, a, tex) self.wait() line_moving.add_updater( lambda x: x.become(line_ref.copy()).rotate( theta_tracker.get_value() * DEGREES, about_point=rotation_center ) ) a.add_updater( lambda x: x.become(Angle(line1, line_moving, radius=0.5, other_angle=False)) ) tex.add_updater( lambda x: x.move_to( Angle( line1, line_moving, radius=0.5 + 3 * SMALL_BUFF, other_angle=False ).point_from_proportion(0.5) ) ) self.play(theta_tracker.animate.set_value(40)) self.play(theta_tracker.animate.increment_value(140)) self.play(tex.animate.set_color(RED), run_time=0.5) self.play(theta_tracker.animate.set_value(350)) .. tip:: You can use multiple ValueTrackers simultaneously. .. manim:: MovingDots class MovingDots(Scene): def construct(self): d1,d2=Dot(color=BLUE),Dot(color=GREEN) dg=VGroup(d1,d2).arrange(RIGHT,buff=1) l1=Line(d1.get_center(),d2.get_center()).set_color(RED) x=ValueTracker(0) y=ValueTracker(0) d1.add_updater(lambda z: z.set_x(x.get_value())) d2.add_updater(lambda z: z.set_y(y.get_value())) l1.add_updater(lambda z: z.become(Line(d1.get_center(),d2.get_center()))) self.add(d1,d2,l1) self.play(x.animate.set_value(5)) self.play(y.animate.set_value(4)) self.wait() .. manim:: MovingGroupToDestination class MovingGroupToDestination(Scene): def construct(self): group = VGroup(Dot(LEFT), Dot(ORIGIN), Dot(RIGHT, color=RED), Dot(2 * RIGHT)).scale(1.4) dest = Dot([4, 3, 0], color=YELLOW) self.add(group, dest) self.play(group.animate.shift(dest.get_center() - group[2].get_center())) self.wait(0.5) .. manim:: MovingFrameBox :ref_modules: manim.mobject.svg.tex_mobject :ref_classes: MathTex SurroundingRectangle class MovingFrameBox(Scene): def construct(self): text=MathTex( "\\frac{d}{dx}f(x)g(x)=","f(x)\\frac{d}{dx}g(x)","+", "g(x)\\frac{d}{dx}f(x)" ) self.play(Write(text)) framebox1 = SurroundingRectangle(text[1], buff = .1) framebox2 = SurroundingRectangle(text[3], buff = .1) self.play( Create(framebox1), ) self.wait() self.play( ReplacementTransform(framebox1,framebox2), ) self.wait() .. manim:: RotationUpdater :ref_methods: Mobject.add_updater Mobject.remove_updater class RotationUpdater(Scene): def construct(self): def updater_forth(mobj, dt): mobj.rotate_about_origin(dt) def updater_back(mobj, dt): mobj.rotate_about_origin(-dt) line_reference = Line(ORIGIN, LEFT).set_color(WHITE) line_moving = Line(ORIGIN, LEFT).set_color(YELLOW) line_moving.add_updater(updater_forth) self.add(line_reference, line_moving) self.wait(2) line_moving.remove_updater(updater_forth) line_moving.add_updater(updater_back) self.wait(2) line_moving.remove_updater(updater_back) self.wait(0.5) .. manim:: PointWithTrace :ref_classes: Rotating :ref_methods: VMobject.set_points_as_corners Mobject.add_updater class PointWithTrace(Scene): def construct(self): path = VMobject() dot = Dot() path.set_points_as_corners([dot.get_center(), dot.get_center()]) def update_path(path): previous_path = path.copy() previous_path.add_points_as_corners([dot.get_center()]) path.become(previous_path) path.add_updater(update_path) self.add(path, dot) self.play(Rotating(dot, radians=PI, about_point=RIGHT, run_time=2)) self.wait() self.play(dot.animate.shift(UP)) self.play(dot.animate.shift(LEFT)) self.wait() Plotting with Manim =================== .. manim:: SinAndCosFunctionPlot :save_last_frame: :ref_modules: manim.mobject.coordinate_systems :ref_classes: MathTex :ref_methods: Axes.plot Axes.get_vertical_line_to_graph Axes.input_to_graph_point Axes.get_axis_labels class SinAndCosFunctionPlot(Scene): def construct(self): axes = Axes( x_range=[-10, 10.3, 1], y_range=[-1.5, 1.5, 1], x_length=10, axis_config={"color": GREEN}, x_axis_config={ "numbers_to_include": np.arange(-10, 10.01, 2), "numbers_with_elongated_ticks": np.arange(-10, 10.01, 2), }, tips=False, ) axes_labels = axes.get_axis_labels() sin_graph = axes.plot(lambda x: np.sin(x), color=BLUE) cos_graph = axes.plot(lambda x: np.cos(x), color=RED) sin_label = axes.get_graph_label( sin_graph, "\\sin(x)", x_val=-10, direction=UP / 2 ) cos_label = axes.get_graph_label(cos_graph, label="\\cos(x)") vert_line = axes.get_vertical_line( axes.i2gp(TAU, cos_graph), color=YELLOW, line_func=Line ) line_label = axes.get_graph_label( cos_graph, "x=2\pi", x_val=TAU, direction=UR, color=WHITE ) plot = VGroup(axes, sin_graph, cos_graph, vert_line) labels = VGroup(axes_labels, sin_label, cos_label, line_label) self.add(plot, labels) .. manim:: ArgMinExample class ArgMinExample(Scene): def construct(self): ax = Axes( x_range=[0, 10], y_range=[0, 100, 10], axis_config={"include_tip": False} ) labels = ax.get_axis_labels(x_label="x", y_label="f(x)") t = ValueTracker(0) def func(x): return 2 * (x - 5) ** 2 graph = ax.plot(func, color=MAROON) initial_point = [ax.coords_to_point(t.get_value(), func(t.get_value()))] dot = Dot(point=initial_point) dot.add_updater(lambda x: x.move_to(ax.c2p(t.get_value(), func(t.get_value())))) x_space = np.linspace(*ax.x_range[:2],200) minimum_index = func(x_space).argmin() self.add(ax, labels, graph, dot) self.play(t.animate.set_value(x_space[minimum_index])) self.wait() .. manim:: GraphAreaPlot :save_last_frame: :ref_modules: manim.mobject.coordinate_systems :ref_methods: Axes.plot Axes.get_vertical_line_to_graph Axes.get_area Axes.get_axis_labels class GraphAreaPlot(Scene): def construct(self): ax = Axes( x_range=[0, 5], y_range=[0, 6], x_axis_config={"numbers_to_include": [2, 3]}, tips=False, ) labels = ax.get_axis_labels() curve_1 = ax.plot(lambda x: 4 * x - x ** 2, x_range=[0, 4], color=BLUE_C) curve_2 = ax.plot( lambda x: 0.8 * x ** 2 - 3 * x + 4, x_range=[0, 4], color=GREEN_B, ) line_1 = ax.get_vertical_line(ax.input_to_graph_point(2, curve_1), color=YELLOW) line_2 = ax.get_vertical_line(ax.i2gp(3, curve_1), color=YELLOW) riemann_area = ax.get_riemann_rectangles(curve_1, x_range=[0.3, 0.6], dx=0.03, color=BLUE, fill_opacity=0.5) area = ax.get_area(curve_2, [2, 3], bounded_graph=curve_1, color=GREY, opacity=0.5) self.add(ax, labels, curve_1, curve_2, line_1, line_2, riemann_area, area) .. manim:: PolygonOnAxes :ref_classes: Axes Polygon class PolygonOnAxes(Scene): def get_rectangle_corners(self, bottom_left, top_right): return [ (top_right[0], top_right[1]), (bottom_left[0], top_right[1]), (bottom_left[0], bottom_left[1]), (top_right[0], bottom_left[1]), ] def construct(self): ax = Axes( x_range=[0, 10], y_range=[0, 10], x_length=6, y_length=6, axis_config={"include_tip": False}, ) t = ValueTracker(5) k = 25 graph = ax.plot( lambda x: k / x, color=YELLOW_D, x_range=[k / 10, 10.0, 0.01], use_smoothing=False, ) def get_rectangle(): polygon = Polygon( *[ ax.c2p(*i) for i in self.get_rectangle_corners( (0, 0), (t.get_value(), k / t.get_value()) ) ] ) polygon.stroke_width = 1 polygon.set_fill(BLUE, opacity=0.5) polygon.set_stroke(YELLOW_B) return polygon polygon = always_redraw(get_rectangle) dot = Dot() dot.add_updater(lambda x: x.move_to(ax.c2p(t.get_value(), k / t.get_value()))) dot.set_z_index(10) self.add(ax, graph, dot) self.play(Create(polygon)) self.play(t.animate.set_value(10)) self.play(t.animate.set_value(k / 10)) self.play(t.animate.set_value(5)) .. manim:: HeatDiagramPlot :save_last_frame: :ref_modules: manim.mobject.coordinate_systems :ref_methods: Axes.plot_line_graph Axes.get_axis_labels class HeatDiagramPlot(Scene): def construct(self): ax = Axes( x_range=[0, 40, 5], y_range=[-8, 32, 5], x_length=9, y_length=6, x_axis_config={"numbers_to_include": np.arange(0, 40, 5)}, y_axis_config={"numbers_to_include": np.arange(-5, 34, 5)}, tips=False, ) labels = ax.get_axis_labels( x_label=Tex("$\Delta Q$"), y_label=Tex("T[$^\circ C$]") ) x_vals = [0, 8, 38, 39] y_vals = [20, 0, 0, -5] graph = ax.plot_line_graph(x_values=x_vals, y_values=y_vals) self.add(ax, labels, graph) Special Camera Settings ======================= .. manim:: FollowingGraphCamera :ref_modules: manim.scene.moving_camera_scene :ref_classes: MovingCameraScene MoveAlongPath Restore :ref_methods: Axes.plot Mobject.add_updater class FollowingGraphCamera(MovingCameraScene): def construct(self): self.camera.frame.save_state() # create the axes and the curve ax = Axes(x_range=[-1, 10], y_range=[-1, 10]) graph = ax.plot(lambda x: np.sin(x), color=BLUE, x_range=[0, 3 * PI]) # create dots based on the graph moving_dot = Dot(ax.i2gp(graph.t_min, graph), color=ORANGE) dot_1 = Dot(ax.i2gp(graph.t_min, graph)) dot_2 = Dot(ax.i2gp(graph.t_max, graph)) self.add(ax, graph, dot_1, dot_2, moving_dot) self.play(self.camera.frame.animate.scale(0.5).move_to(moving_dot)) def update_curve(mob): mob.move_to(moving_dot.get_center()) self.camera.frame.add_updater(update_curve) self.play(MoveAlongPath(moving_dot, graph, rate_func=linear)) self.camera.frame.remove_updater(update_curve) self.play(Restore(self.camera.frame)) .. manim:: MovingZoomedSceneAround :ref_modules: manim.scene.zoomed_scene :ref_classes: ZoomedScene BackgroundRectangle UpdateFromFunc :ref_methods: Mobject.add_updater ZoomedScene.get_zoomed_display_pop_out_animation class MovingZoomedSceneAround(ZoomedScene): # contributed by TheoremofBeethoven, www.youtube.com/c/TheoremofBeethoven def __init__(self, **kwargs): ZoomedScene.__init__( self, zoom_factor=0.3, zoomed_display_height=1, zoomed_display_width=6, image_frame_stroke_width=20, zoomed_camera_config={ "default_frame_stroke_width": 3, }, **kwargs ) def construct(self): dot = Dot().shift(UL * 2) image = ImageMobject(np.uint8([[0, 100, 30, 200], [255, 0, 5, 33]])) image.height = 7 frame_text = Text("Frame", color=PURPLE, font_size=67) zoomed_camera_text = Text("Zoomed camera", color=RED, font_size=67) self.add(image, dot) zoomed_camera = self.zoomed_camera zoomed_display = self.zoomed_display frame = zoomed_camera.frame zoomed_display_frame = zoomed_display.display_frame frame.move_to(dot) frame.set_color(PURPLE) zoomed_display_frame.set_color(RED) zoomed_display.shift(DOWN) zd_rect = BackgroundRectangle(zoomed_display, fill_opacity=0, buff=MED_SMALL_BUFF) self.add_foreground_mobject(zd_rect) unfold_camera = UpdateFromFunc(zd_rect, lambda rect: rect.replace(zoomed_display)) frame_text.next_to(frame, DOWN) self.play(Create(frame), FadeIn(frame_text, shift=UP)) self.activate_zooming() self.play(self.get_zoomed_display_pop_out_animation(), unfold_camera) zoomed_camera_text.next_to(zoomed_display_frame, DOWN) self.play(FadeIn(zoomed_camera_text, shift=UP)) # Scale in x y z scale_factor = [0.5, 1.5, 0] self.play( frame.animate.scale(scale_factor), zoomed_display.animate.scale(scale_factor), FadeOut(zoomed_camera_text), FadeOut(frame_text) ) self.wait() self.play(ScaleInPlace(zoomed_display, 2)) self.wait() self.play(frame.animate.shift(2.5 * DOWN)) self.wait() self.play(self.get_zoomed_display_pop_out_animation(), unfold_camera, rate_func=lambda t: smooth(1 - t)) self.play(Uncreate(zoomed_display_frame), FadeOut(frame)) self.wait() .. manim:: FixedInFrameMObjectTest :save_last_frame: :ref_classes: ThreeDScene :ref_methods: ThreeDScene.set_camera_orientation ThreeDScene.add_fixed_in_frame_mobjects class FixedInFrameMObjectTest(ThreeDScene): def construct(self): axes = ThreeDAxes() self.set_camera_orientation(phi=75 * DEGREES, theta=-45 * DEGREES) text3d = Text("This is a 3D text") self.add_fixed_in_frame_mobjects(text3d) text3d.to_corner(UL) self.add(axes) self.wait() .. manim:: ThreeDLightSourcePosition :save_last_frame: :ref_classes: ThreeDScene ThreeDAxes Surface :ref_methods: ThreeDScene.set_camera_orientation class ThreeDLightSourcePosition(ThreeDScene): def construct(self): axes = ThreeDAxes() sphere = Surface( lambda u, v: np.array([ 1.5 * np.cos(u) * np.cos(v), 1.5 * np.cos(u) * np.sin(v), 1.5 * np.sin(u) ]), v_range=[0, TAU], u_range=[-PI / 2, PI / 2], checkerboard_colors=[RED_D, RED_E], resolution=(15, 32) ) self.renderer.camera.light_source.move_to(3*IN) # changes the source of the light self.set_camera_orientation(phi=75 * DEGREES, theta=30 * DEGREES) self.add(axes, sphere) .. manim:: ThreeDCameraRotation :ref_classes: ThreeDScene ThreeDAxes :ref_methods: ThreeDScene.begin_ambient_camera_rotation ThreeDScene.stop_ambient_camera_rotation class ThreeDCameraRotation(ThreeDScene): def construct(self): axes = ThreeDAxes() circle=Circle() self.set_camera_orientation(phi=75 * DEGREES, theta=30 * DEGREES) self.add(circle,axes) self.begin_ambient_camera_rotation(rate=0.1) self.wait() self.stop_ambient_camera_rotation() self.move_camera(phi=75 * DEGREES, theta=30 * DEGREES) self.wait() .. manim:: ThreeDCameraIllusionRotation :ref_classes: ThreeDScene ThreeDAxes :ref_methods: ThreeDScene.begin_3dillusion_camera_rotation ThreeDScene.stop_3dillusion_camera_rotation class ThreeDCameraIllusionRotation(ThreeDScene): def construct(self): axes = ThreeDAxes() circle=Circle() self.set_camera_orientation(phi=75 * DEGREES, theta=30 * DEGREES) self.add(circle,axes) self.begin_3dillusion_camera_rotation(rate=2) self.wait(PI/2) self.stop_3dillusion_camera_rotation() .. manim:: ThreeDSurfacePlot :save_last_frame: :ref_classes: ThreeDScene Surface class ThreeDSurfacePlot(ThreeDScene): def construct(self): resolution_fa = 24 self.set_camera_orientation(phi=75 * DEGREES, theta=-30 * DEGREES) def param_gauss(u, v): x = u y = v sigma, mu = 0.4, [0.0, 0.0] d = np.linalg.norm(np.array([x - mu[0], y - mu[1]])) z = np.exp(-(d ** 2 / (2.0 * sigma ** 2))) return np.array([x, y, z]) gauss_plane = Surface( param_gauss, resolution=(resolution_fa, resolution_fa), v_range=[-2, +2], u_range=[-2, +2] ) gauss_plane.scale(2, about_point=ORIGIN) gauss_plane.set_style(fill_opacity=1,stroke_color=GREEN) gauss_plane.set_fill_by_checkerboard(ORANGE, BLUE, opacity=0.5) axes = ThreeDAxes() self.add(axes,gauss_plane) Advanced Projects ================= .. manim:: OpeningManim :ref_classes: Tex MathTex Write FadeIn LaggedStart NumberPlane Create :ref_methods: NumberPlane.prepare_for_nonlinear_transform class OpeningManim(Scene): def construct(self): title = Tex(r"This is some \LaTeX") basel = MathTex(r"\sum_{n=1}^\infty \frac{1}{n^2} = \frac{\pi^2}{6}") VGroup(title, basel).arrange(DOWN) self.play( Write(title), FadeIn(basel, shift=DOWN), ) self.wait() transform_title = Tex("That was a transform") transform_title.to_corner(UP + LEFT) self.play( Transform(title, transform_title), LaggedStart(*[FadeOut(obj, shift=DOWN) for obj in basel]), ) self.wait() grid = NumberPlane() grid_title = Tex("This is a grid", font_size=72) grid_title.move_to(transform_title) self.add(grid, grid_title) # Make sure title is on top of grid self.play( FadeOut(title), FadeIn(grid_title, shift=UP), Create(grid, run_time=3, lag_ratio=0.1), ) self.wait() grid_transform_title = Tex( r"That was a non-linear function \\ applied to the grid" ) grid_transform_title.move_to(grid_title, UL) grid.prepare_for_nonlinear_transform() self.play( grid.animate.apply_function( lambda p: p + np.array( [ np.sin(p[1]), np.sin(p[0]), 0, ] ) ), run_time=3, ) self.wait() self.play(Transform(grid_title, grid_transform_title)) self.wait() .. manim:: SineCurveUnitCircle :ref_classes: MathTex Circle Dot Line VGroup :ref_methods: Mobject.add_updater Mobject.remove_updater :ref_functions: always_redraw class SineCurveUnitCircle(Scene): # contributed by heejin_park, https://infograph.tistory.com/230 def construct(self): self.show_axis() self.show_circle() self.move_dot_and_draw_curve() self.wait() def show_axis(self): x_start = np.array([-6,0,0]) x_end = np.array([6,0,0]) y_start = np.array([-4,-2,0]) y_end = np.array([-4,2,0]) x_axis = Line(x_start, x_end) y_axis = Line(y_start, y_end) self.add(x_axis, y_axis) self.add_x_labels() self.origin_point = np.array([-4,0,0]) self.curve_start = np.array([-3,0,0]) def add_x_labels(self): x_labels = [ MathTex("\pi"), MathTex("2 \pi"), MathTex("3 \pi"), MathTex("4 \pi"), ] for i in range(len(x_labels)): x_labels[i].next_to(np.array([-1 + 2*i, 0, 0]), DOWN) self.add(x_labels[i]) def show_circle(self): circle = Circle(radius=1) circle.move_to(self.origin_point) self.add(circle) self.circle = circle def move_dot_and_draw_curve(self): orbit = self.circle origin_point = self.origin_point dot = Dot(radius=0.08, color=YELLOW) dot.move_to(orbit.point_from_proportion(0)) self.t_offset = 0 rate = 0.25 def go_around_circle(mob, dt): self.t_offset += (dt * rate) # print(self.t_offset) mob.move_to(orbit.point_from_proportion(self.t_offset % 1)) def get_line_to_circle(): return Line(origin_point, dot.get_center(), color=BLUE) def get_line_to_curve(): x = self.curve_start[0] + self.t_offset * 4 y = dot.get_center()[1] return Line(dot.get_center(), np.array([x,y,0]), color=YELLOW_A, stroke_width=2 ) self.curve = VGroup() self.curve.add(Line(self.curve_start,self.curve_start)) def get_curve(): last_line = self.curve[-1] x = self.curve_start[0] + self.t_offset * 4 y = dot.get_center()[1] new_line = Line(last_line.get_end(),np.array([x,y,0]), color=YELLOW_D) self.curve.add(new_line) return self.curve dot.add_updater(go_around_circle) origin_to_circle_line = always_redraw(get_line_to_circle) dot_to_curve_line = always_redraw(get_line_to_curve) sine_curve_line = always_redraw(get_curve) self.add(dot) self.add(orbit, origin_to_circle_line, dot_to_curve_line, sine_curve_line) self.wait(8.5) dot.remove_updater(go_around_circle)