Canonical Computational Core for Growth-Topology-Based Virtual Lumber I

Canonical Computational Core for Growth-Topology-Based Virtual Lumber I provides the reproducible computational foundation for constructing three-dimensional virtual lumber from growth-based wood geometry. The framework represents annual-ring geometry, establishes longitudinal annual-ring correspondence and topology, constructs a continuous chronological field, derives local growth and material frames including spiral grain, and transfers these fields to virtually sawn boards.The archived notebook is the canonical source for generating virtual_lumber_core.py and includes numerical consistency checks for annual-ring topology, chronology, moving-section geometry, material-frame construction, board mapping, and field inheritance. Documentation figures describe the computational workflow, field dependencies, and mapping between mathematical objects and public APIs.This record accompanies Growth-Topology-Based Virtual Lumber I and its Supplementary Methods for Growth-Topology-Based Virtual Lumber I. The Supplement provides detailed derivations, numerical verification, notation, and worked examples, whereas this canonical core preserves the executable computational definitions and public APIs used by both the manuscript and the Supplement. The executable Jupyter notebook is retained as the source of truth, while the accompanying code-free PDF provides a readable description of the mathematical structure, computational architecture, API organization, and verification framework.