> ## Documentation Index
> Fetch the complete documentation index at: https://docs.altoura.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Anchoring & QR Codes
> How Altoura Frontline lines digital content up with the real world — the QR anchor, step-level anchor gems, and the tethered lines that guide the worker.
This page is for anyone who will author or run procedures. It explains the one idea that makes mixed-reality guidance work: **spatial anchoring** — how a printed QR code and step-level anchor gems keep 3D models, media, and instructions in exactly the right physical place.
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## Why anchoring matters
A procedure's 3D models, gems, and instructions are placed at real positions in a physical workspace. For that content to appear in the right place every time — for every worker, on every session — the device needs a fixed reference point in the room. That reference point is the **QR anchor**.
* **Authors** scan the QR code, then place 3D models, gems, media, and instructions in the physical space. Everything is stored **relative to the QR's position**.
* **Operators** scan the **same QR at the same physical location**, so all authored content appears exactly where the author placed it.
Once a QR is used to anchor a procedure, it **must remain in the exact same physical position** for that procedure. Moving the QR later shifts the anchor and misaligns every model, gem, and instruction placed against it — for both authors and operators.
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## The QR code
The **Altoura Frontline QR code** is a physical marker: you print it once, fix it to a stable surface at the work site, and reuse it for every procedure anchored to that location.
Use the QR code provided by Altoura for anchoring. Third-party or self-generated QR codes might not work reliably with the Frontline QR scan flow. Download the print-ready PDF, printing guidance, and scanning tips from [QR for Author and Operator](/frontline/procedures/qr-anchor/qr-code).
Practical rules of thumb from the field:
* **One QR per anchor location** — a dedicated printout per physical workspace, kept fixed.
* **High contrast, matte, flat.** Glossy or wrinkled printouts cause scan failures.
* **Look straight at it** from roughly 30–60 cm for the fastest lock.
* **Re-scan if drift appears.** If placed content looks off-position, exit and re-scan the QR to re-anchor — a **rescan** updates the QR anchor, and every placed item repositions with it, preserving the author's relative placement.
When you enter a procedure on your device, the app prompts you through the scan: a QR scan instruction panel appears, the camera interface opens, and after a QR is detected you **confirm the anchor** before the procedure opens. The device walkthroughs cover this flow in detail — [HoloLens: Anchor with QR](/frontline/hololens/operate/anchor-with-qr) and [iPad: Anchor with QR](/frontline/ipad/operate/anchor-with-qr).
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## Anchor gems — step-level markers
The QR anchor aligns the whole procedure. **Anchor gems** go one level finer: they link an individual step to a specific point in the environment.
* In **Author Mode**, each step panel has a diamond-shaped **gem icon**. The author clicks it, points at a location in the physical space, and places the anchor there.
* A visible **tethered line** (thread) connects the step panel to the placed anchor.
* Gem placement is **per step** — one step may have an anchor while the next has none. Navigating between steps updates the tether to match that step's configuration.
* Gems are stored **relative to the QR anchor**, so they survive re-anchoring.
### What the operator sees
In **Operator Mode**, anchor gems are visible exactly as authored but are not configurable — operators can't place, move, or remove them. When a step has a gem, the tethered line connects the step panel to the anchor and updates dynamically as the worker moves, showing:
* **Where the step applies**
* **Which physical location is relevant**
* **Where attention or action is required**
If the author placed no gem for a step, no gem or tether appears for that step.
***
## The mental model
| Layer | What it anchors | Who controls it |
| -------------- | -------------------------------------------------- | ----------------------------------------------------------------- |
| **QR anchor** | The whole procedure's content to the room | Scanned by both authors and operators; position fixed at the site |
| **Anchor gem** | One step to one precise point, via a tethered line | Placed by the author; viewed (read-only) by the operator |
Next: see where authored, anchored content gets published and how it reaches operators in [How Content Flows](/frontline/overview/concepts/how-content-flows).