Frequently asked questions

Will it run on my iPhone?

You need an iPhone with an A12 Bionic chip or newer — that's iPhone XS, XR, 11 and everything after — running iOS 17 or later. The A12 floor is Apple's, not ours: ARKit body tracking simply isn't available below it. If your device can't do body tracking, the app tells you so on launch rather than failing quietly.

Do I need LiDAR?

No. LiDAR is optional. On Pro models it sharpens the floor estimate, which slightly improves how the anatomy is scaled to the body. On every other iPhone the app falls back to ARKit's own estimate and a silhouette-based height signal.

Does it work on iPad?

Corpus 4AR is published as an iPhone app. The App Store lists iPhone compatibility only, and the interface is portrait iPhone throughout.

Can I use it on myself?

Not the way you'd take a selfie — the app uses the rear camera only. To see your own anatomy, prop the phone up 1–3 m away or hand it to someone else. In practice most people use it in pairs, which is also how it works best for teaching.

Can it track two people at once?

Point it at one person at a time. ARKit's body tracking is designed around a single tracked subject, and that's the case Corpus 4AR is built and tuned for.

Is it available in other languages?

The interface is English only. Anatomical labels can be switched between English and Latin (Terminologia Anatomica), and search accepts a number of non-English aliases — coração, œsophage, hepar — but the app itself is not localised.

How accurate is the placement?

Scale is estimated, not measured. The app sizes the body geometrically from the floor plane, the person's silhouette and ARKit's own estimate — there is no calibration step. It states a typical rendered-height accuracy of about ±5 cm when the subject is standing with a clear view of the floor, degrading when they're seated or crouched. Treat that as the app's own stated expectation rather than a validated measurement, and never as a measurement of the person in front of you.

Is this person's real anatomy?

No. Every mesh comes from a single standardised reference model. Real anatomy varies with pose, respiration, body composition, prior surgery and congenital variation. The overlay shows roughly where a structure sits in a typical body of that size — not where it sits in this body.

What does the tracking pill mean?

It reports how much to trust the current overlay, and you can tap it for a plain-language explanation inside the app.

• Searching — no stable body yet
• Approximate — tracking, still settling
• Strong — locked on

Why do the organs drift or jitter?

Usually framing or light. Keep the whole torso and head in frame, stand 1–3 m back, avoid strong backlight, and face the camera — extreme side profiles confuse body tracking. Over a long session you can also use Reset Tracking in settings to restart ARKit's world tracking. The field guide covers this properly.

Does it work in the dark?

No. ARKit needs a reasonably well-lit room to find a body. If you want the anatomy to stand out against a bright room, use the camera-dim slider — it darkens the camera feed only, leaving the rendered structures at full brightness.

Does it need an internet connection?

No. Everything runs on your device — body tracking, rendering, search, info cards. Release builds contain no reachable server call, no login and no sync.

Is my camera feed uploaded anywhere?

No. Camera frames are processed in real time by ARKit on your iPhone and are never stored or transmitted by the app. The App Store privacy label for Corpus 4AR reads Data Not Collected. The full detail is in the privacy policy.

Can I record a clip or take a photo?

Yes. A shutter button saves a still with the overlay to your Photos library, and the record button captures video of the live overlay — up to 60 seconds, with optional narration through the microphone. You review the clip in the app before deciding whether to keep or share it. Nothing is written to Photos until you ask for it.

If you record another person, getting their consent is your responsibility — see section 7 of the Terms.

What's actually in the app?

36 organs, 57 bone structures and 221 muscles — 314 structures you can search, isolate and render. Every one of them is listed on this site. Organs and bones also carry a full info card with the Latin name, function, common conditions and surface landmark; muscles are rendered and searchable but have no info card.

Why are muscles unlabelled?

Because 221 simultaneous labels are unreadable. Muscles are drawn without labels by default; focus one from search and it gets a label of its own.

Where do the 3D models come from?

From the BodyParts3D / Anatomography library, © The Database Center for Life Science (DBCLS), Japan, licensed under CC BY-SA 2.1 Japan. Corpus 4AR converts the source meshes to USDZ, decimates them so they render on a phone, and applies uniform scale factors; the attribution and licence link are also shown inside the app.

Is it really free?

Yes — every feature, no trial, no subscription, no locked layers. There's an optional tip between $2 and $50 if the app is useful to you. It unlocks nothing, because nothing is locked.

Is it a medical device?

No. Corpus 4AR is an educational and reference tool. It is not intended for diagnosis, treatment, monitoring or any clinical decision-making, and it has not been evaluated or cleared by any regulator. Section 2 of the Terms sets this out in full.