The Mathematics of 3D Printing Slicing: STL Geometry, Ray-Casting & Toolpaths is an open-access engineering monograph and interactive instructional module edited and published by Prep4Uni.Online. This work provides an analytical, undergraduate-to-graduate level treatment of the computational geometry foundations required to translate three-dimensional surface meshes into layer-by-layer machine toolpaths.
Aligned with international accreditation frameworks—including the Washington Accord (WA1–WA5) and EUR-ACE First/Second Cycle—this monograph presents the explicit mathematical derivations, vector intersection proofs, and topological rules governing modern additive manufacturing slicers.
Key Topics Covered:1. STL Surface Topology: Structure of unstructured triangular meshes, surface normal vectors, coordinate validation, and z-interval bounds.2. Facet-Plane Intersections: Parametric linear interpolation solving for boundary segments Sk on cutting planes z = zk, including degenerate vertex-plane handling via epsilon shifts.3. Interior Classification: The Jordan Curve Theorem and 2D Ray-Casting Even-Odd Parity algorithm for identifying internal voids and deposition zones.4. Toolpath Generation: Trajectory planning comparing concentric perimeter offsets and parallel raster hatch infills.5. Three-Tier Engineering Assessment: 8 foundational questions, 7 conceptual/failure-analysis debugging cases, and 6 multi-step quantitative worked problems with explicit engineering interpretations.
Canonical Online Interactive Resource:https://prep4uni.online/stem/physical-technologies/industrial-and-manufacturing-technologies/additive-manufacturing-3d-printing/mathematics-of-slicing/