Ranim

examples/hello_ranim

examples/ranim_logo

Ranim is an animation engine crate implemented in pure rust, inspired heavily by Manim and jkjkil4/JAnim.

Warning

Ranim is now WIP. It only supports some basic items and animations, the apis are unstable and may change frequently, the documentation is also not complete.

Related:

• AzurIce/ranim-doc: rustdoc for main
• AzurIce/ranim-book: ranim book
• AzurIce/ranim-one-shot: one-shot attempts with ranim
• AzurIce/ranim-bench: benchmarks for ranim

Dependencies

Runtime dependencies:

• ffmpeg: encode videos Ranim will try to use ffmpeg from system's path environment variable first, if no ffmpeg is found, ranim will automatic download ffmpeg to the current working dir.

Installation

Published release: v0.2.1

[dependencies]
ranim = "0.2.1"

Documentation: v0.2.1 guide and API reference.

Development: v0.3 (unreleased)

[dependencies]
ranim = { git = "https://github.com/AzurIce/ranim" }

The following examples target the v0.3 App/Plugin API.

Project entry

Define scenes as Rust functions in a library or module, then register their descriptors in an App. Native hosts run the CLI; WASM hosts export the project to JavaScript. For a package named my-animation:

# Cargo.toml
[dependencies]
ranim = { git = "https://github.com/AzurIce/ranim" }

# Needed when exporting app() from the WASM host.
[target.'cfg(target_arch = "wasm32")'.dependencies]
wasm-bindgen = "0.2.129"

// src/lib.rs — reusable scene definition; no CLI, GPU, or browser startup.
use ranim::{items::vitem::geometry::Square, prelude::*};

#[scene]
pub fn hello(scene: &mut RanimScene) {
    scene.play(CameraFrame::default().show().with_duration(2.0));
    scene.play(Square::new(2.0).show().with_duration(2.0));
}

// src/main.rs — the same binary target serves native and WASM.
use ranim::prelude::*;

fn project() -> ranim::RanimApp {
    let mut app = App::new();
    app.add_scenes([my_animation::hello::scene()]);
    app.build()
}

#[cfg(not(target_arch = "wasm32"))]
fn main() {
    run_cli(project());
}

#[cfg(target_arch = "wasm32")]
fn main() {}

#[cfg(target_arch = "wasm32")]
#[wasm_bindgen::prelude::wasm_bindgen]
pub fn app() -> ranim::wasm::WasmApp {
    ranim::wasm::WasmApp::new(project())
}

#[scene] generates hello::scene() for explicit registration. App and Plugin are Bevy types. Plugins optionally group scenes, resources, and render configuration; app.build() finalizes the project for either host. See project entry for setup and platform bindings.

Experimental scene hot reload

Enable subsecond with cmd-preview and use Dioxus CLI:

dx serve --hotpatch --desktop --example hello_ranim --features subsecond --args preview

Patches rebuild the scene and pause at the previous time, preserving the window/GPU. This is scene reconstruction, not state migration; structural changes require a restart. Native only. The flake pins a dx workspace fix; that CLI/runtime combination awaits end-to-end validation. See limitations.

Custom render setup

Built-in camera, vector, and mesh rendering needs no setup when items is enabled. For custom types or composite outputs, register a RenderSetup with an ExtractPlugin<T> matching the complete frame type. See render extraction.

Web examples

Examples share native/WASM entries in one binary target. Browser UI and playback use independent viewport and controls components, with an expandable timeline and synchronized Web Audio. Native preview uses egui.

cargo examples build arc  # WASM + bindings + optimization
CARGO_BUILD_JOBS=4 just website-preview arc  # build and serve locally

Run inside nix develop, then open http://127.0.0.1:8000/examples/arc.html and select App. See examples for layout and commands.

Command line interface

Command	Purpose
preview [SCENE]	Interactive native preview; defaults to the first scene
output [SCENES...]	Render declared outputs and capture marks; defaults to all scenes
render <SCENE>	One default-settings export, ignoring declared outputs and captures
inspect scenes|tree|frame	Inspect registration, animation trees, or evaluated items

cargo run -- preview hello
cargo run -- output hello
cargo run -- inspect frame hello --at 1.5
cargo run --example hello_ranim -- preview  # repository example

See CLI reference for options. Some examples require typst or gltf; native export without the UI uses --no-default-features --features anims,cmd-render.

Feature Flags

Defaults are anims, items, and cmd-preview.

Feature	Capability
items	Built-in item types and their re-export; optional dependency
anims	Built-in animations and their re-export; enables items
render	GPU rendering API and WASM canvas host; independent of built-in items and native commands
cmd-render	Native CLI (output, render, inspect) and offline export; enables render
cmd-preview	Native egui preview and PCM playback, including the export panel; enables cmd-render
typst	Typst text support; enables items
gltf	glTF import; enables items
audio-decode	Audio file decoding with symphonia and resampling with rubato
subsecond	Experimental native scene hot reload with Dioxus CLI

--no-default-features keeps core evaluation and project assembly. Native command dependencies are excluded from WASM.

The native Profiler panel shows GPU passes, CPU spans, and upload stats. Enable GPU timestamps with RANIM_PROFILE_GPU=1 (adds a per-frame device poll), or upload tracking with RANIM_PROFILE_UPLOAD=1.

Contributing

Book and website builds

The root Notist.toml groups book/ and website/ into a workspace; each member keeps its own configuration. Inside nix develop, run just book, just website, or just publications to build both. Outputs are notist-output/ranim-book/ and notist-output/ranim-website/, with independent deployment URLs. Use notist serve -p ranim-book or notist serve -p ranim-website for preview. Website builds generate example pages without rendering or uploading media; see the website guide for WASM and media preparation.

See CONTRIBUTING.md for guidelines.

Design

Once the design is stablized, I may write about it.

For now, you can check out the code.

Aknowledgements

• 3b1b/manim
• ManimCommunity/manim
• jkjkil4/JAnim

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