Manim

Manim Animation Skill (manimgl / 3b1b)

You are an expert at creating animations using Grant Sanderson's manimgl (3b1b/manim, version 1.7.2).

> IMPORTANT: This project uses manimlib (3b1b's version), NOT manim (community edition). Always import with from manimlib import *.

Source lookup

To find the installed manimlib source, run:

python3 -c "import manimlib; print(manimlib.__path__[0])"

When you need to verify a class signature, method, or parameter before writing code:

1. First check the reference file in the same directory as this SKILL.md: reference.md
2. If you need deeper detail, read the actual source file from the manimlib install path. Key files:

• mobject/geometry.py — Line, Circle, Polygon, Arrow, Rectangle, etc.
• mobject/three_dimensions.py — Sphere, Cylinder, Torus, Cube, Prism
• mobject/coordinate_systems.py — Axes, ThreeDAxes, NumberPlane
• mobject/types/vectorized_mobject.py — VMobject, VGroup, DashedVMobject
• mobject/types/surface.py — Surface, SGroup
• mobject/types/image_mobject.py — ImageMobject
• mobject/svg/tex_mobject.py — Tex, TexText
• mobject/svg/text_mobject.py — Text, MarkupText, Code
• animation/creation.py — ShowCreation, Write, DrawBorderThenFill
• animation/fading.py — FadeIn, FadeOut, FadeTransform
• animation/transform.py — Transform, ReplacementTransform, MoveToTarget
• animation/composition.py — AnimationGroup, Succession, LaggedStart
• animation/indication.py — Indicate, Flash, FlashAround
• animation/rotation.py — Rotate, Rotating
• scene/scene.py — Scene, ThreeDScene
• camera/camera_frame.py — CameraFrame (reorient, setfieldof_view, etc.)
• constants.py — Colors, directions, math constants

NEVER guess or hallucinate a method or parameter. If unsure, read the source first.

Example environments

Pre-built environment templates are in the templates/ directory next to this file:

• basic_3d_scene.py — Minimal 3D scene with ground, objects, camera setup
• drone_environment.py — Drone with ground grid, altitude line, frustum visualization
• math_2d_scene.py — 2D scene with axes, graphs, and annotations
• terrain_surface.py — 3D terrain height field with contour coloring

Use these as starting points. Copy and modify rather than writing from scratch.

Coordinate system (manimgl)

manimgl uses a Y-up coordinate system:

• X = Right, Y = Up, Z = Out (toward viewer)
• RIGHT = [1,0,0], UP = [0,1,0], OUT = [0,0,1]
• Diagonals: UL, UR, DL, DR
• Edges: TOP, BOTTOM, LEFT_SIDE, RIGHT_SIDE

If converting from ENU (East-North-Up): manim_vec = [east, up, north]

Scene structure pattern

from manimlib import *

class MyScene(ThreeDScene):  # or Scene for 2D
    def construct(self):
        # 1. Set up camera
        frame = self.camera.frame
        frame.reorient(-20, 72)           # azimuth, elevation (degrees)
        frame.set_field_of_view(55 * DEG)
        frame.set_height(10)
        frame.move_to(ORIGIN)

        # 2. Build mobjects
        obj = Sphere(radius=0.5, color=BLUE)
        obj.move_to([1, 2, 0])

        # 3. Animate
        self.play(FadeIn(obj), run_time=1.0)
        self.wait(0.5)

        # 4. Transform / morph
        new_obj = Sphere(radius=1.0, color=RED).move_to([1, 2, 0])
        self.play(Transform(obj, new_obj), run_time=1.5)

Running animations

IMPORTANT: Always render to file with -w so the user can view the result. After rendering, open the video so the user can watch it.

# Render to file
manimgl scene_file.py ClassName -w --hd

# After rendering, open the video for the user to view:
code ./videos/ClassName.mp4

The output video lands in ./videos/ClassName.mp4. After every successful render, always run code to open the video so the user can view it directly in their editor.

Key patterns and best practices

Grouping objects

group = VGroup(line1, line2, line3)      # for VMobjects (vectorized)
group = Group(sphere1, sphere2)           # for non-VMobjects (3D shapes)

Fixed-in-frame overlays (HUD/labels on top of 3D)

label = Text("Title", font_size=24, color=WHITE)
label.to_corner(UR, buff=0.3).fix_in_frame()

Animating camera movement

self.play(frame.animate.reorient(90, 5), run_time=2.0)
self.play(frame.animate.move_to([2, 1, 0]), run_time=1.5)

Color palette (3b1b defaults)

BLUE_E, BLUE_D, BLUE_C (=BLUE), BLUE_B, BLUE_A  (dark to light)
Same pattern for RED, GREEN, YELLOW, PURPLE, GREY, TEAL, MAROON, GOLD, PINK
WHITE, BLACK, GREY_A through GREY_E

Styling

line.set_stroke(color=RED, width=3.0, opacity=0.8)
polygon.set_fill(color=BLUE, opacity=0.3)
mob.set_color(YELLOW)

Common animation combos

# Simultaneous animations
self.play(FadeIn(a), ShowCreation(b), Write(c), run_time=1.5)

# Sequential
self.play(FadeIn(a))
self.play(ShowCreation(b))

# Staggered
self.play(LaggedStart(*[FadeIn(m) for m in group], lag_ratio=0.15))

# Morphing between states
self.play(Transform(old_group, new_group), run_time=1.8)

Value tracking for parameter animation

tracker = ValueTracker(0)
obj = always_redraw(lambda: Circle(radius=tracker.get_value()))
self.play(tracker.animate.set_value(3), run_time=2)

What to avoid

• Do NOT use from manim import * (community edition). Use from manimlib import *.
• Do NOT use Create() — use ShowCreation() instead (manimgl naming).
• Do NOT use Scene.renderer — manimgl uses Scene.camera directly.
• Do NOT use config.frame_rate — pass via CLI flags or default_config.yml.
• Sphere, Cube, Prism are NOT VMobjects — use Group() not VGroup() to contain them.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: av-simi2
• Source: av-simi2/claude-manim-skill
• License: MIT

Install and usage instructions live in the source repository linked above.