Getting Started: Polar Filament with OpenTag3D

We respect Prusa’s work on OpenPrintTag and share its goal of creating an open RFID ecosystem. We have been in contact with Prusa about RFID standards for roughly a year.

The primary reason we cannot adopt OpenPrintTag is its physical tag and reader requirements.

Prusa’s current implementation uses NFC-V tags and specialized antenna hardware. NFC-V is not backward compatible with the inexpensive, widely available NFC Type 2 tags used by OpenTag3D. Likewise, a reader designed only for Prusa’s NFC-V implementation cannot read ordinary NTAG213, NTAG215, or NTAG216 tags.

The required hardware does not fit our existing spool design, and we have not found a reliable source for the required tags that satisfies our manufacturing and domestic-sourcing requirements.

OpenPrintTag is so custom that even Prusa couldn’t adopt it without redesigning its spool.

This is the immediate showstopper: we cannot manufacture around a tag that does not fit our spools and that we cannot reliably source.

Even if the physical compatibility problem were resolved, we still have concerns about parts of the data-storage format, inefficient use of limited tag space, lookup tables, reserved identifiers, and how portions of the standard are centrally governed. Those concerns are secondary to the hardware problem.

We will continue following OpenPrintTag’s development. If the hardware and adoption barriers are resolved, we would gladly reconsider supporting it.

Bambu Lab tags are proprietary and digitally signed. Bambu printer firmware rejects modified or newly created tags that do not contain a valid Bambu signature.

Third-party manufacturers cannot create genuinely compatible custom tags without Bambu’s private signing key or modified printer firmware.

Technical details are available in the Bambu Research Group RFID Tag Guide.

TigerTag

We reviewed TigerTag’s standard offline format and determined that it does not store enough of the information we want to include with our filament.

It also relies on centrally maintained lookup tables. Instead of storing values such as material and manufacturer names directly, the tag stores numeric identifiers. Software must consult a reference list to determine what those identifiers mean.

The official identifiers and their meanings are controlled and maintained by a single entity. Even when a copy of the lookup table is available offline, compatibility still depends on that centrally managed namespace.

TigerTag does not use NDEF records. Its data occupies fixed locations in raw tag memory, which prevents the same tag from conveniently carrying TigerTag alongside other NDEF-based formats. A normal TigerTag payload and an OpenTag3D NDEF record would compete for the same memory.

TigerTag+

TigerTag+ adds more functionality through product IDs, signatures, and information retrieved from TigerTag-controlled services.

We do not want our tags’ essential functionality to depend on a third-party database being maintained indefinitely. Hosting costs money, and a centrally controlled service could later be restricted or placed behind a paywall. Tags should remain useful if a company disappears, changes direction, or decides to monetize access.

For our requirements, TigerTag’s offline format is not complete enough, while TigerTag+ introduces central dependencies we specifically want to avoid.

Open source means a format or its software is publicly documented and available for others to inspect or implement.

Decentralized means no single company controls whether it continues to work, who may participate, or how essential identifiers and data are managed.

An “open source” RFID system may still give one company control over:

• Lookup tables and identifier assignments
• Reserved IDs and data ranges
• Which changes enter the official specification
• Required servers or online services
• Commercial certification or signature programs

That organization can change direction, restrict participation, lock down future versions, or charge for important services even if the community disagrees.

OpenTag3D stores essential information directly on the tag in an independently readable form. Reading it does not require an account, internet connection, company-controlled database, or permission from a central authority.

No company, including Polar Filament, owns or controls OpenTag3D. The community governs the project collectively, and the published specification can be forked and maintained independently if any contributor disappears or changes direction. Existing tags remain readable, and development can continue without a company’s permission.