manim

What this skill does

# Manim

Build mathematical animations programmatically using Python. Manim renders scenes to video files with precise control over every visual element.

## Quick Start

```python
from manim import *

class MyScene(Scene):
    def construct(self):
        # Create objects
        circle = Circle(color=BLUE)
        text = MathTex(r"e^{i\pi} + 1 = 0")

        # Animate
        self.play(Create(circle))
        self.play(Write(text))
        self.wait(1)
        self.play(FadeOut(circle, text))
```

Run with: `manim -pql scene.py MyScene`

## Workflow

1. **Define a Scene class** inheriting from `Scene` (or `ThreeDScene` for 3D)
2. **Implement `construct()`** method
3. **Create Mobjects** (mathematical objects) - shapes, text, graphs
4. **Animate with `self.play()`** - use animation classes like `Create`, `Transform`, `FadeIn`
5. **Render** using CLI: `manim -pqh scene.py SceneName`

## Core Concepts

### Mobjects
All visible objects inherit from `Mobject`. Common types:
- **Geometry**: `Circle`, `Square`, `Line`, `Arrow`, `Polygon`
- **Text**: `Text`, `MathTex`, `Tex`
- **Graphs**: `Axes`, `NumberPlane`, `FunctionGraph`
- **3D**: `Sphere`, `Cube`, `ThreeDAxes`
- **Groups**: `VGroup` to combine objects

### Animations
Pass to `self.play()`:
- **Creation**: `Create`, `Write`, `FadeIn`, `GrowFromCenter`
- **Transform**: `Transform`, `ReplacementTransform`, `MoveToTarget`
- **Indication**: `Indicate`, `Flash`, `Circumscribe`
- **Removal**: `FadeOut`, `Uncreate`

### Positioning
```python
obj.move_to(ORIGIN)          # Move to point
obj.shift(RIGHT * 2)         # Relative shift
obj.next_to(other, UP)       # Position relative to another
obj.align_to(other, LEFT)    # Align edge
```

### Animation Parameters
```python
self.play(Create(obj), run_time=2)           # Duration
self.play(Create(obj), rate_func=smooth)     # Easing
self.play(anim1, anim2)                       # Simultaneous
self.play(Succession(anim1, anim2))          # Sequential
self.play(LaggedStart(*anims, lag_ratio=0.5)) # Staggered
```

## Common Patterns

### Mathematical Equation
```python
eq = MathTex(r"\int_0^1 x^2 \, dx = \frac{1}{3}")
self.play(Write(eq))
```

### Function Graph
```python
axes = Axes(x_range=[-3, 3], y_range=[-1, 5])
graph = axes.plot(lambda x: x**2, color=BLUE)
label = axes.get_graph_label(graph, label="x^2")
self.play(Create(axes), Create(graph), Write(label))
```

### Value Tracking (Animated Numbers)
```python
tracker = ValueTracker(0)
number = DecimalNumber(0).add_updater(
    lambda m: m.set_value(tracker.get_value())
)
self.add(number)
self.play(tracker.animate.set_value(10), run_time=2)
```

### 3D Scene
```python
class My3D(ThreeDScene):
    def construct(self):
        axes = ThreeDAxes()
        sphere = Sphere()
        self.set_camera_orientation(phi=75*DEGREES, theta=45*DEGREES)
        self.play(Create(axes), Create(sphere))
        self.begin_ambient_camera_rotation(rate=0.2)
        self.wait(3)
```

### Transform Between States
```python
circle = Circle()
square = Square()
self.play(Create(circle))
self.play(Transform(circle, square))  # circle becomes square
```

## CLI Reference

```bash
manim scene.py SceneName      # Render scene
manim -p scene.py SceneName   # Preview after render
manim -s scene.py SceneName   # Save last frame only

# Quality flags
-ql  # Low (480p @ 15fps)
-qm  # Medium (720p @ 30fps)
-qh  # High (1080p @ 60fps)
-qk  # 4K (2160p @ 60fps)
```

## Key Gotchas

1. **Transform mutates first object**: After `Transform(a, b)`, reference `a` (now looks like `b`), not `b`
2. **Use ReplacementTransform** to avoid confusion: replaces `a` with `b` in scene
3. **Mobjects are mutable**: Use `.copy()` to avoid unintended changes
4. **LaTeX requires `r` prefix**: `MathTex(r"\frac{1}{2}")` not `MathTex("\frac{1}{2}")`
5. **3D requires ThreeDScene**: Regular `Scene` won't render 3D properly
6. **`self.add()` is instant**: Use `self.play(FadeIn(...))` for animated appearance

## References

- **Full API** (animations, mobjects, scenes, colors, constants): See [references/api.md](references/api.md)
- **Quick lookup** (tables, patterns, CLI): See [references/quick-reference.md](references/quick-reference.md)