An open letter toThe 3D Printing Industry
The 3D design economy is being hollowed out by piracy. Designers spend weeks sculpting a miniature that sells for $8 — and within 48 hours it's redistributed freely across Discord, Telegram, and marketplace repacks. The tools to stop this exist. What's missing is the ecosystem to deliver them at scale.
The problem is structural
STL files are unprotected by design. The format — created in 1987 for stereolithography — is a raw list of triangles with no concept of ownership, licensing, or access control. Every STL sold online is immediately redistributable by anyone who downloads it.
Slicers open any STL without question. Marketplaces deliver raw files to buyers. No part of the current ecosystem gives designers the ability to control what happens to their work after purchase.
We built STL Shield to fix this. The .stlx container encrypts STL files with AES-256-GCM, embeds forensic watermarks that survive slicer re-export, and ties access to per-buyer license tokens. But for the protection to be seamless, the industry needs to build it in.
The .stlx format
Open specification. MIT-licensed reference implementation. No vendor lock-in.
// .stlx binary container — open specification
// ────────────────────────────────────────────
0x00 magic: "STLSHLD\0" [8 bytes]
0x08 version: u16 [2 bytes] // 0x0001
0x0A header_len: u32 [4 bytes]
0x0E header_json: JSON [variable] // product_id, iv, algo
0x.. ciphertext: bytes [variable] // AES-256-GCM encrypted mesh
0x.. gcm_tag: bytes [16 bytes] // authentication tag
// cipher: AES-256-GCM (per-file unique key)
// key wrap: HKDF-SHA256 under master key
// watermark: 5 mesh methods + 4 G-code methods
// Full spec: stlshield.com.au/docs/stlx-format-spec
To every slicer manufacturer
We're asking you to add native .stlx support. The integration is a single Rust shared library callable from your existing file-open pipeline. Decrypted mesh stays in memory — no disk write needed.
To every marketplace
Accept .stlx as an upload format alongside STL. Issue license tokens as part of the purchase flow. Designers protect their files. Buyers get seamless access. Your platform becomes where premium content lives.
What we're asking
Adopt .stlx as a supported file format
The spec is open. The reference implementation is MIT-licensed. No licensing fees. No exclusivity. No lock-in.
Join the format working group
We're forming an open working group to standardise .stlx across the industry. Your engineering input will make it better.
Run a closed beta with us
Real designers. Real buyers. Real files. Let's prove the buyer experience is zero-friction before any public launch.
Add your voice
Every endorsement strengthens the case. When we present to slicer and marketplace teams, we'll show them exactly how many designers are demanding encrypted file protection.
Get in touch
Whether you build slicers, run a marketplace, or design files — we want to talk.
Slicer integration
[email protected]Marketplace partnerships
[email protected]General & press
[email protected]