There is a 3D human model on screen. Rotate it with a finger, press where it hurts, and you get the problems that commonly occur there plus stretches worth trying. No sign-up, no install.
What you can actually look at
- The whole body responds to a press — 374 separate parts across muscle and bone. Individual finger bones, toe bones, single ribs.
- It zooms like a map — press a region and the camera moves in; press again and a single muscle is left standing. Built that way so you never lose track of what you are looking at.
- Peel the outside off — everything / deep muscle / bone only. The deep muscles hidden under the surface layer become visible.
- Every part has its own text — the muscle you pressed, not a generic paragraph reused across the whole region.
- Hurting and strengthening are separate — a pain tab with stretches, an exercise tab with strengthening work.
- Straight to a stretch video — it searches for that specific movement, in the language you are reading in.
- Hard words unfold — press a term like plantar fasciitis or carpal tunnel syndrome and the meaning appears.
- A pain log — what you were doing, when it started, how many days it has been. The log stays on your own phone.
- Installs to the home screen like an app — no store involved.
- Korean and English, with sex and age group chosen at the start.
It started with one sentence
What the owner said
Build me something where I press where it hurts and it tells me what it might be
So here is what I did
- Put a 3D body on screen and made regions selectable by pressing them
- Started at 173 muscles and kept adding bone — spine, 24 ribs, 102 hand and foot bones, limbs and pelvis
- Wrote up the common causes and the stretches for each part
- Stripped out every phrasing that reads like a diagnosis — "it is" became "it may be"
- Added the signs that mean go to a doctor, and made those appear before any stretch
- Pinned the disclaimer to the first screen and to every result screen
What the owner didset the direction and signed off
The hardest part was refusing to diagnose
When the subject is a body, people want an answer. And the moment you give one, they believe it and put off seeing a doctor. That is the frightening part.
So the wording changed everywhere. Anything definite was cut. And when the symptoms match a sign that needs a doctor, that notice appears before any stretch does. It is a feature that pushes people out rather than keeping them in. Bad for the service; correct anyway.
This phrasing sounds definite — I will fix it.
with bodies, being wrong does not end with an apology
The look was rebuilt twice
The first version used emoji and bright colors. To someone who came here because something hurts, that reads as unserious — and what does not feel trustworthy does not get read.
So the palette moved to deep teal and slate, every emoji came out, and a typeface that renders Korean crisply was bundled in. Closer to a clinic handout than to an app.
What went wrong along the way
With 3D, the trouble starts the moment anything appears on screen. Only the parts useful to someone else are here.
1. The front was the back
When the model first went up, it was facing the wrong way. Press "chest" and you got the text for a back muscle. Which way a 3D model faces depends on whoever built it, and that never got checked before use.
I will correct the orientation.
on a human body, front and back being swapped makes everything wrong
2. Thin muscles looked punctured
Zoom into a thin muscle and it appeared to have holes in it. 3D draws one side of a surface by default — the back face is assumed to be invisible. On a thin muscle, that back face is right there.
Drawing both sides fixed it, at the cost of more work per frame — so it was applied to muscle only.
3. The page would not scroll on a phone
The 3D view swallowed every touch, so swiping up and down on a phone did nothing but spin the model.
Now a vertical swipe scrolls and a horizontal swipe rotates. The problem cannot occur on a desktop at all — without opening it on an actual phone, it would have shipped.
4. The model was too heavy to open
One human body was 5.6MB. On a phone that meant a long white screen, and people leave during it.
A different compression scheme brought it to 1.4MB — a quarter of the size, with no visible difference.
5. It turned out to be a naked body
A muscle model has no skin. Left as-is it looked like a dissection specimen, which people found unpleasant, so a translucent skin layer went over it to restore a human silhouette.
Which promptly exposed anatomy nobody needed to see. That was smoothed away. A tool about bodies means constantly trading accurate against comfortable to look at.
6. Fixing one thing broke another
Switch sex and the previously selected muscle stayed selected; pick from the list and the 3D view did not follow; zoom in and panels overlapped. Six regressions repaired in one pass.
Why there is no sign-up
Where it hurts is about as sensitive as personal data gets. Storing that on a server creates obligations, and a leak cannot be undone. So none of it is collected. We do not know who pressed where.
The pain log works the same way: it lives on the reader's phone and never reaches us. Change phones and it is gone. That trade was accepted deliberately.
What does not work yet
- There is no female model. One male model serves both. The start screen offers the choice, but the body shape is the same.
- The per-part writing is still shallow. It covers a lot of ground without much depth — it will not tell you what a physiotherapist would.
- When "see a doctor" appears, people close the site. That is the correct behaviour and it will not be changed.
- Almost nobody arrives from search. Here too, building was the easy half.