Manim

manim

Manim (Manim Community edition) renders animations from Python: a Scene subclass whose construct() plays animations on mobjects. The render lands as MP4 under out/. Tools: $MANIM (the pinned CLI), $MANIM_PYTHON (its interpreter). Never install another.

Render (the verdict comes with it)

"$MANIM_PYTHON" "$MANIM_TOOLCHAIN/render.py" scenes/intro.py Intro            # quick: 480p15, the default
"$MANIM_PYTHON" "$MANIM_TOOLCHAIN/render.py" -qm scenes/intro.py Intro        # medium: 720p30
"$MANIM_PYTHON" "$MANIM_TOOLCHAIN/render.py" -qh scenes/intro.py Intro        # final: 1080p60
"$MANIM_PYTHON" "$MANIM_TOOLCHAIN/render.py" --format gif scenes/x.py Name    # a gif instead

render.py is manim render with the same flags, output and tracebacks, plus what the pane needs: --media_dir out --save_sections, a live progress file (the pane plays each animation as it is written and shows a failure with its line), a record of the render's animations and chapters, and the verdict at the end. Use it for every render; plain $MANIM render still works but the pane sees less. Renders go to out/videos/<file>/<quality>/<Scene>.mp4. Render at -ql while iterating (fast), -qh once at the end.

Chapters

The pane shows a scene's sections as chapters — on the timeline, in a list, as 1…9 keys. Mark every beat of the storyboard with a section, named the way a chapter title reads:

def construct(self):
    self.next_section("The question")
    ...
    self.next_section("Squares on the sides")
    ...
    self.next_section("9 + 16 = 25")

Three to eight sections for a 20–60 s scene; a name is two to five words; the first call comes before the first play. A section with no animation is dropped. Keep names stable between renders: the pane marks a chapter "changed" or "new" by its name.

Writing scenes

• One file per scene under scenes/; class name = the scene's name; a docstring says what it shows.
• Mobjects: Text, MathTex (needs LaTeX — check command -v latex first; without it, formulas are Text(...) with Unicode superscripts and the render still lands), Circle, Square, Rectangle, Line, Arrow, Dot, Axes, NumberPlane, VGroup, Table, BarChart, ImageMobject.
• Animations: Create, Write, FadeIn/FadeOut (with shift=), Transform, ReplacementTransform, MoveToTarget, Indicate, Circumscribe, LaggedStart, AnimationGroup, .animate (e.g. self.play(dot.animate.shift(RIGHT * 2))), run_time=, rate_func=.
• Layout: .next_to(other, DOWN, buff=0.3), .to_edge(UP), .move_to(ORIGIN), .scale(), .arrange(RIGHT) on groups. The frame is 14.2 × 8 units; keep text within ±6 horizontally.
• Timing: 0.6–1.2 s per beat, self.wait(0.5) between ideas, never more than one new idea on screen at a time. A 60-second explainer is 8–12 beats.
• Look: dark background (self.camera.background_color = "#0b0b0c"), one accent colour, a sans-serif via Text(..., font="Helvetica Neue"), big type (scale 0.8–1.4).
• Graphs and data: Axes(x_range=[0, 10, 1], y_range=[0, 5, 1]), axes.plot(lambda x: ...), axes.get_graph_label, BarChart(values, bar_names=...).
• Camera moves: subclass MovingCameraScene and animate self.camera.frame.

Rules

• Save early: a first render within the first minute (title + one beat), then add beats.
• Every beat is a section (see Chapters): a proof or an explainer arrives chaptered.
• Every request that says "explain" is a sequence: what it is, why it matters, the mechanism, the result. One scene, or one scene per section for long ones.
• Assets (images, data) live under assets/; reference them relatively.
• A render that fails prints a Python traceback (and the pane shows the error and its line); fix the line it names, render again. The pane keeps playing the last good render meanwhile.