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name: ui-integration description: "Guides Meshroom PySide6/QML application startup, Scene/UIGraph integration, QML imports, viewers, status monitoring, and display-dependent troubleshooting." disable-model-invocation: true metadata: disco-role: operating license: NOASSERTION

Meshroom UI Integration

Use this route for launching Meshroom's desktop UI, inspecting MeshroomApp, connecting QML to the graph/scene model, or diagnosing PySide6/QML/display failures.

Read First

• UI reference
• QML and scene workflows
• Troubleshooting
• Run scripts/check_ui_imports.py for headless import/QML-path checks; it does not start the event loop by default.

Launch Choices

# Source checkout, Unix-like
PYTHONPATH=$PWD python meshroom/ui
# or
./start.sh

The UI parser accepts an optional project .mg path or image folder plus --import, --importRecursive, --save, --new, --latest, --output, --pipeline, --submitLabel, and --env-help.

Initialization Model

MeshroomApp initializes pipelines, parses arguments, initializes PySide6, registers UI component types, creates a QmlInstantEngine, creates a Scene/UIGraph, and exposes graph/viewer helpers as QML context properties. The UI is a bridge over the core graph engine, not a second graph implementation.

Headless Boundary

• Importing meshroom.ui.app verifies Python/PySide6 module compatibility only.
• Full launch can require a display server, OpenGL/native drivers, QML Scene3D modules, and optional QtAliceVision plugins.
• Use MESHROOM_OUTPUT_QML_WARNINGS=1 when the only visible message is QQmlApplicationEngine failed to load component.
• Use MESHROOM_INSTANT_CODING=1 only during QML development; it enables file watching/reload and adds resource overhead.

For graph mutation, serialization, and status semantics route to core-graph-engine. For CLI startup/import/save options route to cli-pipeline-execution.