Drop any 3D file here
STL, OBJ, STEP, 3MF, or any format: we compute the SHA-256 in your browser, nothing is uploaded.
Computing SHA-256…
How verification works
Every file uploaded to ModelDirectory.org is fingerprinted with SHA-256, a one-way hash that uniquely identifies the exact bytes in a file. We store that fingerprint (never the file itself for verification purposes) alongside the upload date and creator.
When you drop a file here, your browser computes its SHA-256 locally; the file never leaves your device. We then query our database for that fingerprint. If it matches a registered model, we show you when it was first registered and whether the registration is anchored on the Polygon blockchain.
Blockchain anchoring means the fingerprint was written to an immutable smart contract on Polygon mainnet. Our registry contract is 0x687F2e6F96288Ac58fe22E2Eb000D1a628aEEB65, public on Polygonscan, so even if ModelDirectory.org shuts down you can read every stamp straight off the chain. Bitcoin anchoring through OpenTimestamps works the same way: check a proof at the OpenTimestamps verifier.
A SHA-256 match answers one question only: is this the exact same file? Separately, most of the catalog also carries a geometric shape fingerprint that recognizes the same object across re-exports and re-meshes; we use it internally for duplicate detection. The full story is on the provenance page.