mesh-slicing

A C++20 library that slices 3D triangle meshes (STL) into 2D layers, handles contour offsetting, perimeters, and generates infill patterns.

Features

• Multi-threaded triangle-plane intersection (std::thread)
• Line-based ASCII and binary STL loaders
• Adaptive epsilon tolerance (scales with mesh bounding box)
• Winding detection and normalization (CCW outer loops, CW holes)
• Island building (outer contours + inner holes with AABB spatial pruning)
• Clipper2-based offsetting with multi-fragment handling
• Perimeters (concurrent outer/hole shelling)
• Infill patterns: line, grid, hex
• Advanced debug export to SVG and JSON (batch multi-layer rendering, grid overlays, scale bars, and metadata)

Dependencies

• C++20 compiler
• CMake 3.16+
• Clipper2 (fetched automatically via CMake)

Build

mkdir build
cd build
cmake ..
make -j

Testing

cd build
ctest --output-on-failure

Project Structure

include/        - Public headers (triangleMesh.h, sliceLayer.h, offset.h, infill.h, etc.)
src/            - Implementation files
examples/       - Usage examples (example.cpp)
tests/          - Unit test suite (GoogleTest / CTest)

Core Implementation Notes

• Intersection: Slices triangles at a target Z height, filtering fully coplanar triangles and handling on-plane vertices. Duplicates are collapsed using an adaptive epsilon (max_dim * 1e-7).
• Threading: sliceAtZ splits mesh triangles into chunks processed across hardware concurrency threads.
• Path Handling: Loaders accept standard std::filesystem::path inputs.

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Purpose Demonstrates geometric reasoning, slicing algorithms, contour reconstruction, offsetting, infill generation, modular C++ design, and test-driven development. Acts as a reference implementation for building slicing engines or toolpath planners.