Shipping large CAD and BIM archives securely on encrypted drives

Why CAD and BIM archives are hard to move#

CAD and BIM archives are hard to move because their meaning sits in the relationships between files, not in any single file. A Revit model may depend on linked architectural, structural and MEP models, imported CAD, point clouds and a shared parameter file, while an AutoCAD drawing may rely on xrefs, fonts and plot styles stored elsewhere on the server.

Size is the second problem. Point clouds, rendered images, site photo libraries and years of model backups push project folders to sizes that make ordinary file-sharing links slow or unreliable. Sensitivity is the third: models carry user names, client names and building layouts, so they should leave the firm only after preparation and approval.

Three ways to hand over a large archive#

The three practical routes are seller-hosted access, an encrypted drive and a staged transfer. Each trades convenience against control, and the right one depends on archive size, how much of it the recipient needs and how comfortable IT is with outside access to firm systems.

Seller-hosted access deserves more attention than it usually gets. A read-only share in the firm's own cloud tenant, with credentials that expire on a set date and access logs the firm reviews, lets a recipient pull only what it needs and avoids physical media altogether. The trade-off is that the firm pays for storage and any download charges, and IT must actually revoke the access when the window closes.

SourceX never hosts multi-terabyte datasets. Large deliveries stay in the seller's own storage or ship on encrypted drives, which keeps the firm in control of the master copy from start to finish.

Packaging models so they still open on the other side#

Packaging a CAD or BIM archive means gathering every dependency and making paths relative, so the recipient can open models without broken links. Do it on a prepared copy, never on the live project folder.

Then run a test open on a clean workstation with no access to the firm's network. If a link breaks there, it will break for the recipient too.

• 1Detach Revit models from central on the copy, so nobody can synchronize back to the firm's central file.
• 2Collect linked RVT, CAD, IFC and point cloud files into the package and repath each link to a relative location.
• 3Bundle AutoCAD drawings with their xrefs, fonts and plot styles using a transmittal tool such as eTransmit.
• 4Record the authoring software and release for every model, because Revit files open only in the same or a newer release.
• 5Flatten deep folder structures that can break copying on Windows because of long file paths.
• 6Leave out backup folders, local copies, journal files and temp files unless the approved scope includes them.

Encrypting the drive and protecting the key#

Encrypting the drive means the whole volume is unreadable without a key that travels separately. Use full-volume encryption, either a hardware-encrypted drive with a PIN or software such as BitLocker To Go or VeraCrypt, so a lost parcel exposes nothing readable.

Create a hash manifest before the drive leaves, listing every file path with a SHA-256 hash, and keep a copy at the firm. The manifest can travel with the drive or by email; the key or PIN goes by a different channel and only after the recipient confirms the package arrived sealed.

Test the drive before it ships. Unlock it on a second machine using only the key and the written instructions the recipient will receive, open a sample of models, and run the hash check yourself. A drive that fails at the firm's desk would have failed at the recipient's.

Load only the approved package. If the archive was prepared to remove personal data and client identifiers, the drive should hold that prepared copy and nothing else from the server, including no stray working folders or native files outside scope.

Chain-of-custody checklist for a drive handover#

A chain-of-custody record shows who held the drive at each point, so either party can prove what was sent and what arrived. Keep the record short and fill it in at every handover rather than reconstructing it afterward.

Illustrative: a multidisciplinary A/E firm ships its BIM archive#

Illustrative: a fictional architecture and engineering firm agrees to deliver a de-identified package of healthcare and education projects built from Revit models, Navisworks coordination files and issued PDF sets. Point clouds from existing-conditions scans make the package too large for a transfer link.

The digital practice leader prepares the copy on an isolated server, detaches the models, strips user names from worksharing data, repaths links and runs a test open on a clean laptop. The approved package goes onto two encrypted drives: one is shipped and one stays with the firm as the reference copy. The recipient confirms the seal, receives the key by phone, matches every hash and signs the custody log.

The firm's master archive never leaves its own storage, and at the end of the license term the shipped drive is wiped and a certificate is filed with the contract, as the agreement requires.

How SourceX handles large AEC deliveries#

SourceX handles large AEC deliveries as the last step of the SourceX five-step transaction, after Supply, Rights, Preparation and Approval. Delivery uses the seller's own storage or encrypted drives, and the handover method, the access or drive details and the date are recorded against the transaction.

A delivery is not marked complete until either files are uploaded or the external handover is recorded. The SourceX Evidence Packet then ties the shipped package to its provenance, licensing rights, permitted use, privacy record and release authorization, so the firm can show exactly what left its control and under which terms.