Explained · 40 second read

Digital effects that move
the instant your face does.

In short: face tracking finds key points on your face, such as your eyes, nose, mouth and jawline, many times a second, then glues digital effects to those points so they move and rotate exactly as you move. Flip the switch to see the points, then the effect.

Points off

The dots are the tracked points. The dog ears and nose are pinned to them, so they tilt and shift exactly as the face does.

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What it tracks

Roughly 70+ points, dozens of times a second

The camera doesn't need to know your face. It only needs to keep finding the same handful of regions, frame after frame.

Eyes Corners, lids and pupils, so blinks and gaze direction can be read.
Nose Bridge and tip, a stable anchor for anything worn on the face.
Mouth Corners and lip line, so smiles, talking and open-mouth triggers register.
Jawline The outer edge of the face, used to size and rotate effects correctly.

Curious about the full mechanism? Read how a Snapchat Lens gets built.

What it can do

Three ways the points get used

Same landmark map, three very different results depending on what gets attached to it.

Color and makeup Lip tint, blush or a skin tone shift that follows the exact contour of your face.
3D objects Glasses, ears or a mask that sits on your head and turns exactly as it turns.
Expression triggers Open your mouth or raise your eyebrows and the effect changes state on cue.
Needs a face in frame No face visible to the camera means no points to track, so the effect simply doesn't appear.
Not for objects or hands A product on a table or a hand gesture uses a different kind of tracking entirely, built for a different shape.
Breaks at extreme angles Turn too far to the side or drop the lighting too low and the system loses enough points to hold the lock.
Not concept art. Shipped work.

Two face-tracked filters we built

House of the Dragon AR Lens for HBO with face transformation
HBO
House of the Dragon Lens
 007 First Light WebAR face filter
007 First Light
WebAR face filter
Now you know how it tracks

Tell us what you want glued to a face.
We'll tell you what it takes to build it.

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Quick answers

What is face tracking?

Face tracking is a camera system that finds key points on your face, such as your eyes, nose, mouth and jawline, many times a second. Digital effects are glued to those points, so they move and rotate exactly the way your head and expressions do.

How many points does face tracking use?

Most face filters track somewhere around 70 or more points across your face, covering the eyes, eyebrows, nose, mouth and jawline. That map is rebuilt dozens of times every second, so effects stay locked on even while you talk or turn your head.

Does face tracking work on more than one face at once?

Yes. Most modern face tracking systems, including Snapchat's, can find and track several faces in the same camera frame at the same time, applying the same or different effects to each one.

Why does a filter sometimes flicker or fall off my face?

Face tracking needs a clear, well lit view of your face. It can lose lock if your face turns too far to the side, gets partly covered, or the lighting is too dark, because the system can no longer find enough of the key points to place the effect confidently.

Is face tracking the same as face recognition?

No. Face tracking only maps the shape and movement of a face to place effects on it. It does not identify who the face belongs to. Face recognition is a separate technology built to match a face against a known identity.