C++ Exporter [SYNTH-107]

[BrandonPacewic]

SYNTH-107

Initial implementation of Isotope, a C++ Fusion 360 add-in that replaces the existing Python exporter.

This is an opinionated PR; please include an opinionated review.

This includes:

• One-click export experience. No wheel detection yet, so visual verification is the current validation path.
• A build system that correctly locates and links against your installed Fusion C++ API.
• A simplified joint parser compared to the Python implementation that produces the same mirabuf output.
• Full static typing (obviously).
• Mac and Windows support.

Dependencies

• Fusion must be installed.
• CMake and a compiler with C++23 support or later.
• Windows only: MSVC with the C++ Desktop Development workload installed via Visual Studio.

Testing

1. Clone the repo and ensure submodules are initialized (git submodule update --init)
2. From the isotope/ directory, run cmake --workflow --preset build
3. Run cmake --install build to deploy the add-in to Fusion
4. Open Fusion 360, open any robot design, and load the add-in via Shift+S > Add-Ins > isotope > Run
5. Trigger the export and save a .mira file
6. Open the exported file in Synthesis and verify the robot loads correctly

Next Steps

The following will come in subsequent PRs into this feature branch before it replaces the Python exporter:

• Readme and proper documentation
• Updated installers
• Wheel detection
• Field export support
• APS support
• Logging and error messages

[Copilot]

Pull request overview

Introduces Isotope, a new C++ Fusion 360 add-in intended to export Fusion robot designs into mirabuf (.mira) as a replacement for the existing Python exporter, including a CMake-based build/install workflow and initial joint/material/component mapping.

Changes:

• Added Fusion add-in entrypoints (run/stop) and command wiring to trigger export.
• Implemented initial export pipeline: map materials, parts/components, joints, and joint/part hierarchy into mirabuf::Assembly, then serialize to .mira.
• Added CMake build configuration (including protobuf generation via submodule) plus manifest and formatting config.

Reviewed changes

Copilot reviewed 24 out of 30 changed files in this pull request and generated 15 comments.

Show a summary per file

File	Description
isotope/src/util.cpp	GUID helpers and UUID generation used across mappings
isotope/inc/util.h	Shared helpers (type-name checks, Info creation, GUID helpers)
isotope/src/parser.cpp	End-to-end export flow: build Assembly, prompt save dialog, write .mira
isotope/inc/parser.h	Export API declaration
isotope/src/materials.cpp	Appearance + physical material mapping into mirabuf
isotope/inc/materials.h	Materials mapping API declaration
isotope/src/components.cpp	Parts/instances/meshes mapping + rigid group mapping
isotope/inc/components.h	Components/parts mapping API declaration
isotope/src/joints.cpp	Joint + signal mapping and joint graph creation
isotope/inc/joints.h	Joints mapping API declaration
isotope/src/joint_hierarchy.cpp	Joint→parts hierarchy construction logic
isotope/inc/joint_hierarchy.h	Joint hierarchy API declaration
isotope/src/isotope.cpp	Fusion UI integration: adds toolbar panel/button and hooks command handlers
isotope/src/context.cpp	Global Fusion app/UI context initialization and validation
isotope/inc/context.h	Global context struct declaration
isotope/src/config_command.cpp	Command handlers to trigger export
isotope/inc/config_command.h	Command handler class declarations
isotope/isotope.manifest	Fusion add-in manifest metadata
isotope/CMakeLists.txt	CMake project setup, Fusion API linkage, protobuf generation, install step
isotope/CMakePresets.json	Configure/build workflows for debug/release
isotope/.clang-format	Formatting rules for the new C++ code
isotope/.gitignore	Ignore build artifacts/compile commands for the isotope project
.gitmodules	Adds protobuf as a submodule dependency

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[Dhruv-0-Arora]

Testing

I tested isotope and it worked without any issue. We don't need to restart Fusion each time we want to test exporter changes!
I will finish looking through the code tomorrow.

On another note, the exported robot seems to sink into the ground more than the default dozer. I believe this is not an exporter issue however and is rooted in the differences in v9 (right default model) vs v36 (imported left mode) dozer models in fusion.

[Dhruv-0-Arora]

Everything is really well written. There isn't anything that I think is preventing this from getting merged so we can begin to iterate on it.

[PepperLola]

doesn't crash for me anymore