Soul2D

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Soul2D is an experimental 2D model editor with a Rust editing core. The project was previously named VSoul25D. The executables are soul2d-core (headless CLI and MCP host), njc (MCP client) and soul2d-editor (experimental GUI). C ABI symbols, MCP resource identifiers, and the legacy settings directory keep their earlier names for compatibility. It develops the code and workflows inherited from nijigenerate and Inochi2D.

Development status: incomplete. Binary distribution is stopped. This repository is available for source review and development. There is no supported release, installer, Nightly build, or Flatpak distribution. The repository starts from a new Git history; earlier development history is not published.

Current scope

The Rust Session owns document state, revisions, undo/redo, and persistence. Clients are a JSONL CLI, stdio and HTTP MCP, the njc MCP client, and an experimental Rust GUI with an ACP agent panel. The earlier D application has been removed; the migration map lists what replaced each D module and the gaps that remain.

Current work includes INP/INX editing, scene previews, parameter and deformer operations, and bounded inspection and editing of CMO3/CAN3 source files. Support varies by format and operation. Reading or saving a source file does not establish correct rendering or playback in another editor.

In the CAN3 Outline, expand an Image or Guide track and a readable scalar channel to add or delete keys, or edit an anchor value, either handle, or the stored segment type. Apply or discard each edit before saving. Missing or fixed channels are not created.

The following work remains incomplete:

• Packaging: build-aux/osx/BuildUniversal.sh builds an unsigned macOS app bundle from the Rust binaries (universal x86_64 arm64 build run on an arm64 host; the x86_64 slice was only smoke-started under Rosetta; the DMG was built and mounted). The Flatpak manifest and the WiX project are built only by .github/workflows/packaging.yml; neither package was installed on a user's machine, and nothing is signed. See BUILD.md.
• Live click-through verification of the Rust editor beyond one create/undo/save/reopen flow on macOS.
• Full Live2D Cubism authoring, rendering, animation, Physics, and Pose parity.
• Live2D runtime data export beyond the display information and the physics settings: live2d.cdi3.export writes .cdi3.json and live2d.physics3.export writes .physics3.json, while .model3.json, .pose3.json, .exp3.json and .moc3 are not written.
• Native ArtPath evaluation and drawing, Glue creation and editing, and the deformer cases no sample could measure. Stored ArtPath control points can be edited; this does not establish native drawing support (see doc/live2d-authoring.md).
• Production validation of Windows, macOS, and GPU backends such as Metal, CUDA, Vulkan, and ROCm.

Use copies of your models for experiments.

Documentation

• Tutorials: structure a model and define its parameters.
• Command Browser: run actions and tools inside the editor.
• Build from source and translate the editor.
• Developer documentation index: architecture, MCP API, and format conversion map.

English is the canonical language of the documentation. Japanese versions exist for user-facing pages and link back to the English text.

Build from source

See BUILD.md for prerequisites and build commands.

For the Rust core and CLI, after installing Rust and Cargo:

cargo fetch --locked --manifest-path rust/Cargo.toml
./tools/build-rust-core.sh --locked
printf '%s\n' '{"op":"new"}' | ./out/rust/debug/soul2d-core

The CLI returns a JSON response. To use stdio MCP:

./out/rust/debug/soul2d-core --mcp

For the experimental Rust GUI:

./tools/build-rust-core.sh --locked --features gui
./out/rust/debug/soul2d-editor

A graphical desktop and OpenGL are required for the GUI.

Continuous integration

CI runs on pull requests targeting main, pushes to main, and manual dispatches.

• Rust development build compiles the core, CLI, GUI, and test targets on Linux and launches the editor on headless X11 and Wayland.
• Packaging builds the Flatpak bundle and the Windows MSI and smoke-tests them, when the files they are assembled from change.

CI does not execute the test suite, sign anything, or publish releases. A passing build does not establish runtime behavior or format compatibility.

Contribute and report issues

Report Soul2D problems in this repository's issue tracker. Include your commit hash, platform, build command, and reproduction steps. Remove credentials, personal paths, and model data from logs and screenshots. Do not attach third-party models without redistribution permission.

Keep changes focused, preserve unknown source data when editing formats, and verify the behavior you change. Manual checks and optional automated tests are described in BUILD.md.

License and acknowledgements

Project code is licensed under BSD-2-Clause. The original Inochi2D and nijigenerate copyright notices and contributor credits are retained.

Project artwork is self-authored and generated by tools/generate-project-artwork.py (see res/ARTWORK.md); inherited artwork was replaced under the BSD-2-Clause project terms. Bundled fonts, vendored code, and external dependencies have their own notices and terms. See THIRD_PARTY.md. The BSD license does not grant rights to third-party models, branding, or trademarks. Live2D and Cubism names identify formats and compatibility targets; Soul2D is an independent project and is not affiliated with Live2D Inc.

Current third-party notices and publication limits are in THIRD_PARTY.md.