Camera and 3D Reference
MovingCameraScene (2D Camera Control)
`python
class ZoomExample(MovingCameraScene):
def construct(self):
circle = Circle(radius=2, color=BLUE)
self.play(Create(circle))
# Zoom in
self.play(self.camera.frame.animate.set(width=4).move_to(circle.get_top()), run_time=2)
self.wait(2)
# Zoom back out
self.play(self.camera.frame.animate.set(width=14.222).move_to(ORIGIN), run_time=2)
`
Camera Operations
`python
self.camera.frame.animate.set(width=6) # zoom in
self.camera.frame.animate.set(width=20) # zoom out
self.camera.frame.animate.move_to(target) # pan
self.camera.frame.save_state() # save
self.play(Restore(self.camera.frame)) # restore
`
ThreeDScene
`python
class ThreeDExample(ThreeDScene):
def construct(self):
self.set_camera_orientation(phi=60DEGREES, theta=-45DEGREES)
axes = ThreeDAxes()
surface = Surface(
lambda u, v: axes.c2p(u, v, np.sin(u) * np.cos(v)),
u_range=[-PI, PI], v_range=[-PI, PI], resolution=(30, 30)
)
surface.set_color_by_gradient(BLUE, GREEN, YELLOW)
self.play(Create(axes), Create(surface))
self.begin_ambient_camera_rotation(rate=0.2)
self.wait(5)
self.stop_ambient_camera_rotation()
`
Camera Control in 3D
`python
self.set_camera_orientation(phi=70DEGREES, theta=-45DEGREES)
self.move_camera(phi=45DEGREES, theta=30DEGREES, run_time=2)
self.begin_ambient_camera_rotation(rate=0.2)
`
3D Mobjects
`python
sphere = Sphere(radius=1).set_color(BLUE).set_opacity(0.7)
cube = Cube(side_length=2, fill_color=GREEN, fill_opacity=0.5)
arrow = Arrow3D(start=ORIGIN, end=[2, 1, 1], color=RED)
2D text facing camera:
label = Text("Label", font_size=30)
self.add_fixed_in_frame_mobjects(label)
`
Parametric Curves
`python
helix = ParametricFunction(
lambda t: [np.cos(t), np.sin(t), t / (2*PI)],
t_range=[0, 4*PI], color=YELLOW
)
`
When to Use 3D
- - Surfaces, vector fields, spatial geometry, 3D transforms
- - 2D concepts, text-heavy scenes, flat data (bar charts, time series)
When NOT to Use 3D
ZoomedScene — Inset Zoom
Show a magnified inset of a detail while keeping the full view visible:
`python
class ZoomExample(ZoomedScene):
def __init__(self, **kwargs):
super().__init__(
zoom_factor=0.3, # how much of the scene the zoom box covers
zoomed_display_height=3, # size of the inset
zoomed_display_width=3,
zoomed_camera_frame_starting_position=ORIGIN,
**kwargs
)
def construct(self):
self.camera.background_color = BG
# ... create your scene content ...
# Activate the zoom
self.activate_zooming()
# Move the zoom frame to a point of interest
self.play(self.zoomed_camera.frame.animate.move_to(detail_point))
self.wait(2)
# Deactivate
self.play(self.get_zoomed_display_pop_out_animation(), rate_func=lambda t: smooth(1-t))
`
Use cases: zooming into a specific term in an equation, showing fine detail in a diagram, magnifying a region of a plot.
LinearTransformationScene — Linear Algebra
Pre-built scene with basis vectors and grid for visualizing matrix transformations:
`python
class LinearTransformExample(LinearTransformationScene):
def __init__(self, **kwargs):
super().__init__(
show_coordinates=True,
show_basis_vectors=True,
**kwargs
)
def construct(self):
matrix = [[2, 1], [1, 1]]
# Add a vector before applying the transform
vector = self.get_vector([1, 2], color=YELLOW)
self.add_vector(vector)
# Apply the transformation — grid, basis vectors, and your vector all transform
self.apply_matrix(matrix)
self.wait(2)
`
This produces the signature 3Blue1Brown "Essence of Linear Algebra" look — grid lines deforming, basis vectors stretching, determinant visualized through area change.