dcc-mcp-liquigen

Unofficial, local-first DCC-MCP adapter for LiquiGen. It exposes typed, transactional operations for .liquigen node graphs, drives a fixed set of host commands against one exact LiquiGen process/window, and validates LiquiGen-to-Unreal export bundles.

This repository contains no LiquiGen software, presets, projects, license data, or generated assets. LiquiGen and its official examples remain user-installed inputs and are subject to JangaFX's terms.

Water workflow for Unreal Engine 5.8

The primary first-release workflow starts from an official water preset in the user's installed LiquiGen preset directory, such as ball_drop_splash.liquigen. The adapter writes a new project rather than changing the read-only preset, preserves the preset's water simulation and appearance settings, and adds an Unreal-targeted Vertex Animated Texture (VAT) export path.

prepare_unreal_water_project records source provenance, configures the mesh export for Unreal VAT, connects the simulation mesh through typed graph pins, and keeps the output directory explicit. run_export_workflow then loads the exact staged project, drives named playback/export commands, waits for fresh stable files, and validates the canonical VAT bundle before UE handoff.

For UE 5.8 hosts where the SideFX Dynamic Remeshing material produces an empty surface, author_procedural_water_cascade and stage_water_cascade provide a UE-native Niagara/translucent-material fallback. It preserves the real LiquiGen graph timing and export provenance while avoiding a version-specific VAT shader parameter mismatch.

The repository includes a UE 5.8 receiver for the VAT FBX, animation textures, and metadata, plus a flipbook fallback. Automated tests cover graph mutation, bundle validation, host binding, and receiver contracts. A passing CI run does not replace visual acceptance in licensed LiquiGen and Unreal hosts; the official water preset end-to-end viewport result is tracked as a live release gate.

The earlier procedural chain-burst recipe remains available as a secondary graph-authoring example. It is no longer the primary showcase or the visual acceptance target.

Related MCP server: Unreal Engine MCP Server

Typed automation surface

• list_node_schemas discovers installed node types, parameters, and observed pins from local projects.

• inspect_project_graph returns nodes, parameters, keyframes, and connections.

• apply_graph_transaction creates, clones, deletes, configures, animates, connects, and disconnects nodes, and manages groups, notes, project settings, and the active camera in one all-or-nothing write.

• prepare_unreal_water_project stages an installed official water preset to a new path and adds a validated Unreal VAT export route.

• open_project_path uses LiquiGen's project loader for one exact project.

• Fixed host commands expose playback, export, graph framing, tabs, save, the project palette, and the command palette without raw pointer/keyboard input.

• The MCP instance is bound to the exact LiquiGen PID/HWND and becomes unroutable when that identity is no longer live.

Graph writes never overwrite an existing file. Connections are checked against observed node/pin signatures and every completed write is reparsed before it is reported as successful. LiquiGen version matching is advisory: compatibility uses the LiquiGen.exe name, exact window ownership, and named interface probes rather than a host executable hash.

CUA is not required for graph authoring, project loading, playback, export, or bundle validation. Project-owned DCC-CUA is reserved for optional visual viewport acceptance and recording when a typed host operation cannot provide that evidence.

Local development

vx setup
vx just check
vx just build

vx.toml owns the Python, uv, and just versions. justfile is the single entry point for Python and native bridge checks. The native lane uses the installed Windows CMake/MSVC environment through vx --use-system-path.

Install the current source checkout for local evaluation:

vx uv tool install .

Start LiquiGen, resolve its exact PID and HWND, then launch the adapter:

vx uv run dcc-mcp-liquigen `
  --pid <PID> `
  --window-handle <HWND> `
  --executable <ABSOLUTE-LIQUIGEN-EXE> `
  --version <DETECTED-VERSION> `
  --allowed-root <ABSOLUTE-WORKSPACE>

Internal liquigen_setup integration

An internal Rez/Lightbox setup package can export the approved hook location before starting the adapter:

$env:DCC_MCP_LIQUIGEN_COMMAND_HOOK_DLL = "<approved-hook-dll>"

或者由 setup 包直接调用统一启动器：

dcc-mcp-liquigen-launch --executable "<liquigen-exe>" --hook-dll "<approved-hook-dll>" --allowed-root "<workspace>"

The command client reads this variable for each invocation and otherwise uses the installed bridge generation. The setup package remains responsible for starting the licensed LiquiGen executable and passing its exact PID/HWND to dcc-mcp-liquigen; the adapter never starts or modifies the host implicitly.

Use dcc-mcp-cli list, followed by search -> describe -> call. Until the LiquiGen catalog registration lands in dcc-mcp-core, the package entry point can be used directly from this checkout.

Companion menu

The adapter includes an accessible external companion menu. It follows one exact LiquiGen window and invokes only the adapter's typed bridge tools. It does not claim to be a native LiquiGen menu:

vx uv run dcc-mcp-liquigen-menu `
  --pid <PID> `
  --window-handle <HWND> `
  --instance-id <FULL-INSTANCE-UUID> `
  --version <DETECTED-VERSION> `
  --project-path <ABSOLUTE-LIQUIGEN-PROJECT> `
  --export-path <NEW-ABSOLUTE-EXPORT-DIRECTORY>

See the distribution boundary, the automation boundary, the semantic UI bridge contract, and the UE 5.8 workflow. Architecture decisions are recorded under docs/adr.

Project status

0.1.0 is an alpha integration. The tagged-document graph writer and named command bridge are compatibility layers, not a vendor-supported LiquiGen SDK. Keep source projects immutable, retain exact application-version evidence, and verify output in the target DCC before production use.

License

Adapter source is available under the MIT License. LiquiGen is a separate commercial product. This project is not affiliated with or endorsed by JangaFX.