Structuring Native Revit BIM Models into an Open, Self-Describing Package with Tiered Reconstruction Status

Building information models (BIM) are usually stored in proprietary native formats, and reuse outside the authoring application is commonly arranged through IFC exchange, which does not carry every parametric recipe and documentation object of a Revit project. We describe a tool that exports a native Revit model, through the Revit API, into an open package with the extension .rvtmig. The package is a ZIP container holding a JSON manifest, an SQLite database with semantic, parameter, view, sheet and annotation records together with per-element reconstruction recipes, embedded family files, and a binary triangle store (RMS2). The package can be read without Revit using only standard-library tools. When a package is imported into a Revit version, each exported element receives one of five outcomes (native, family, geometry, skipped, failed) according to an explicit fallback chain, and the outcome is recorded. We describe the format, the export and import pipelines and the status model, and explain how the same import path supports version downgrade and IFC export. The paper reports no performance measurements. We specify a validation protocol based on per-category status counts and volume comparisons.