Avatar · Recording guide

How to film someone for a 3‑D avatar, with one camera

This is the protocol for the next recording behind my avatar. It needs one phone, a helper, a printed checkerboard and a tape measure. The camera can move freely between takes, because what the software needs to know about it belongs to the lens, not to where it stands.

Camera: 1, moved between takes
People: Subject + helper
Takes: 8, in 13 short files
Time: About 40 min

Jump to the takes Measurements Checkerboard (A3 PDF)

Before you start

Equipment

One phone or camera, on its main 1× lens.
A tripod, or any stable mount, for the movement takes.
A helper for the handheld orbits.
A checkerboard: print the A3 board (30 mm squares) or, if A3 is not possible, the A4 board (22 mm squares) at 100 % / “Actual size”, never “Fit to page”. Glue it flat to stiff card or foam board, keep the white border, and measure one square to 0.5 mm.
Floor tape and a tape measure.

The room

Even, diffuse light from several sides. Avoid a window whose light changes and hard shadows, and keep the helper’s shadow off the subject during the orbits.
The whole room is background, because the orbit films every direction. No mirrors, TV screens or reflections, and nobody else in frame: the person detector must only ever see the subject. Walls that contrast with the clothes help.
Floor marks: a tape cross where the subject stands, and two foot marks hip-width apart, so every take starts from the same spot.

Camera settings: lock every one before take 0 and never change it mid-session
Setting	Value	Why
Camera app	A manual video app that can lock focus, exposure and white balance, set the shutter, fix the frame rate and turn stabilisation off (for example Blackmagic Camera, free on iPhone and Android). In a stock camera app, a long-press locks only focus and exposure.	The stock app cannot hold every setting below.
Lens and zoom	The main 1× lens only. No zoom, never switched.	The calibration holds for one lens at one zoom.
Orientation	Portrait, for every take.	At 2–2.5 m only portrait fits a whole standing body. One calibration per orientation.
Resolution and rate	4K at a fixed 30 fps (60 fps if the light allows). Any automatic low-light frame rate off.	More pixels on the board and on the body, at a steady rate.
Stabilisation	Off, including electronic and “action” modes. Optical stabilisation usually cannot be disabled; that is fine.	Electronic stabilisation warps every frame differently.
Focus, exposure, white balance	All three locked, with focus on the subject at about 2.5 m.	A focus change shifts the lens model; brightness or colour changes count as error.
Shutter	1/250 s or faster, if the light allows.	The camera moves during the orbits.
HDR, night, beauty, portrait blur	Off.	These alter appearance frame by frame.

Do not close the camera app or tap the screen between takes. If a lock is lost, re-lock it and write that down.

Copy the original files off the phone by cable or file copy, not through a messaging app, which re-compresses the video. On an iPhone, first set Settings › Photos › Transfer to Mac or PC to “Keep Originals”.

The takes

The takes, in order (about 40 minutes)
#	Take	Camera	Length	Files
0	Calibration, start	Helper or tripod; the subject moves the board	45–60 s	`0`
1	Static orbit, A-pose	Helper, handheld	3 passes × 30–40 s	`1a` `1b` `1c`
2	Static orbit, arms up	Helper, handheld	2 passes × 30 s	`2a` `2b`
3	Turn in place	Tripod, front	2 slow turns arms out, 1 arms up	`3`
4	Movement library	Tripod, front; then moved 60–90° to the side	About 20 s per move, per position	`4-front` `4-side`
5	Sealed test	Tripod at a position no other take uses (e.g. 45°)	60 s	`sealed`
6	Calibration, end	As in take 0	45 s	`6`
7	Face and hands (optional, last)	Helper, close	60 s, plus a 45 s board clip	`7` `7-board`

Stop recording between passes and before moving the camera or the tripod, so each pass or position is its own file. Name the files as in the Files column.

Take 0Helper or tripod · 45–60 s

Calibrate the lens

The camera stays still, on the tripod or in the helper’s hands, with the exact recording settings and locks. The subject holds the board about 2–2.5 m away and moves it.
Move it slowly through the whole frame: the centre, all four corners and the edges. Spend most of the time on the corners.
Tilt it by as much as 45° each way: left, right, up and down.
Skip the corners and the lens model there is a guess. The calibration tool warns when one was missed.

Take 1Helper, handheld · 3 passes

Static orbit in an A-pose

The subject stands on the foot marks, arms straight about 45° from the body, palms forward, chin level, eyes on a fixed point, and holds as still as is comfortable, breathing normally.
The helper walks one full, slow circle per pass at a constant 2–2.5 m, keeping the whole body in frame and roughly centred, at the same camera height all the way round.
Pass 1: camera at chest height, level. Pass 2: held high above the helper’s own head, tilted down, to see the top of the head, the shoulders and the tops of the feet. Pass 3: at knee height, tilted up, to see under the chin and arms and the inner legs.
Stop recording after each pass. Rest, then return to the marks and the same pose.

Why a steady distance and height: the tracker treats an orbit like the subject turning in place and holds the body near where it stood in the first frame. Keeping the body centred, at a constant distance and height, keeps that true.

Take 2Helper, handheld · 2 passes

Static orbit, arms up

Arms raised overhead in a wide V, palms forward.
One pass at chest height, one low and tilted up.
This take is meant to remove the grey speckle under the arms.

Take 3Tripod, front · 3 slow turns

Turn in place

The tripod close enough that the body fills most of the frame height, with about 20 cm to spare above the head and below the feet (about 2.5–3 m in portrait). Lens at waist-to-chest height, floor visible.
Two slow turns on the cross with the arms out, then one with the arms raised in a wide V.

Take 4Tripod, two positions · ~20 s per move

Movement library

Same framing as take 3. Each move once slowly, then once at natural speed:

wave with both hands
squats
jumping jacks
march in place
arms raised up and back down
arm circles
side bends
torso twists
a few steps forward and back

Then stop recording, move the tripod 60–90° around the subject, and do the library again as a new file. That is not a second camera, because the two views are not simultaneous, but it gives the model a second viewpoint of every move.

Take 5Tripod, its own position · 60 s

The sealed test

Mixed movement, including at least one move not in take 4: lunges, reaching to the floor, or a slow spin.
Filmed from a tripod position no other take uses, for example 45°.
Name the file sealed, do not open or share it, and keep it apart from the rest.
It is scored once, after every choice about the model is final. That is what makes a later quality claim honest.

Take 6As take 0 · 45 s

Calibrate again

The same as take 0. If the two calibrations disagree, a setting slipped during the session.

Take 7Helper, close · 60 s + 45 s

Face and hands (optional, last)

A slow arc about 1 m from the head: a neutral expression, then a smile.
Each hand held up, front and back, fingers spread, then closed.
This distance needs refocusing, which slightly changes the lens model. Lock focus on the face, and before unlocking, film another board clip (7-board) at about 1 m.

What to wear

Fitted, lightly textured clothes, such as a fitted long-sleeve top and leggings. Avoid all black, which hides both detail and shape, and loose fabric, which moves in ways a body model cannot represent.
The same outfit, hair and shoes in every take. Barefoot, or the shoes the avatar should wear.
Hair tied back, or the same way throughout.
Nothing reflective: no watch, jewellery or glossy logos.

Body measurements

Lengths matter most: they fix where the joints are, which the fit otherwise has to infer. Stand relaxed, use a mirror or the helper to find the landmarks, and record both readings.

Body measurements: twice each, to the nearest 0.5 cm, arms and legs on both sides
Measurement	Landmark / how
Height	Barefoot, heels to a wall, a flat object on the head
Weight
Arm span	Arms straight out at shoulder height, fingertip to fingertip
Sitting height	Seat to the top of the head, sitting upright
Shoulder width	Bony point to bony point on top of each shoulder (acromion), in a straight line: a ruler, or a tape held straight behind the shoulders, not following the curve of the back
Upper arm	Arm hanging straight and relaxed: acromion to the point of the elbow
Forearm	Arm straight: the point of the elbow to the wrist bone on the little-finger side
Hand length	Wrist crease to the middle fingertip
Leg heights	Standing, measured straight up from the floor to: the bony bump on the outside of the upper thigh (it rolls under your fingers when you turn the foot in and out), the knee joint (the soft gap at the side of the knee), and the inner ankle bone
Inseam	Crotch to the floor, standing
Foot length and width	Heel to the longest toe; the widest point across the ball
Head, neck, chest, waist, hip girths	Tape level and snug, not tight; the waist at its narrowest, the hips at their widest
Upper arm, forearm, wrist girths	Widest point, widest point, at the wrist bone
Mid-thigh, calf, ankle girths	Halfway between hip and knee; widest point; narrowest point
Sole thickness	Only if shoes are worn in the takes

Also take one front and one side photo on the tape cross, in the outfit.

Afterwards

What to hand over

The original video files, named as in the takes table.
The board’s measured square size.
A short notes.txt: the camera model, app and settings, the take order, where the tripod stood for takes 3–5, any lock that was lost, and the measurements.

All of it stays on one local machine. Personal video and measurements are never uploaded or committed anywhere.

What is ready, and what is not

Ready, proven on real footage: the single-camera pipeline that built the current avatar from a turn in place and a short movement clip, with a guessed lens.
Built, not yet run on real footage: the checkerboard calibration and the step that prepares frames with the real lens. On simulated recordings the calibration finds the focal length to within 0.15 %, but it meets its accuracy target across the whole image only when the board reaches all four corners, and its strictest test, at the very corners, failed; that is recorded, not hidden. Take 0 is its first real test.
Not built yet: a fit made for the orbit, with the body fixed and the camera moving, and the scoring of this session’s sealed take. Until the orbit fit exists, the orbit is tracked as a turn in place, which has not yet been tried on an orbit.
No helper? A tripod with takes 0 and 3–6 still works: the earlier method, now with a real lens model, fitted clothes, the arms-up turn and full measurements.

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