Tracking, windows, and masks
Follow faces, hands, bodies, contours, and motion; draw tracking looks and keep effects inside a moving window.
BeamTracer FX Rack can draw tracking lines, open a window between your hands, or keep effects inside a face or body. Add Visual Source for your camera or uploaded video, then choose TRACK, HAND FRAME, or MASK. Each effect has its own controls for the tracked area and its appearance.
How do I draw tracking lines on a face, hands or a body?
TRACK watches the visual source, or the picture itself when there is none, and draws over what it finds. Its looks stack, so a face can carry tiles, links and a scan at once, and they move with the music on their own.
- Add TRACK from ADD AN EFFECT. With no visual source showing it brings your camera along (the browser asks the first time); with one showing it follows that. STATUS at the top of its controls says what TRACK sees, for example 2 HANDS · 30 FPS.
- FOLLOW picks what to track: FACE (up to two faces, traced along the eyes, brows, lips and jaw), HANDS (up to two, every finger joint, labeled left and right), FACE + HANDS (both at once; each is found about half as often, so the lines move a little less smoothly), BODY (the joints of one or two people that are in view), OBJECTS (up to six everyday things, named: a person, a cup, a phone, a bottle) or CONTOURS (the strongest edges of the picture, no person needed). The first time you pick one it takes a moment to get ready. When a face, hands or body cannot be found, the looks settle on the contours instead, so a profile or a landscape still gets the print; STATUS says ON CONTOURS.
- Switch the looks on: BOXES + LABELS (corner brackets, a name, a confidence and live coordinates), PLEXUS (points joined to their nearest neighbors; REACH sets how far a line can stretch), CONSTELLATION (the skeleton, small markers on the joints, a ring and a few coordinates), MOSAIC (numbered square tiles cut from the picture at the landmarks, some dark, some inverted, re-dealt on every beat, with an inset of one eye and DEPTH and ROTATION readouts; TILES sets how many, and DEPTH floats them in front of and behind your face and hands, so nearer tiles look bigger, slide further as you move your head and spread out as you lean in; BOXES DEPTH and SHAPES DEPTH do the same for the boxes and the marks) and SCAN (a curtain of hairlines that rise and fall with the music like a quiet spectrum meter, a scan line that sweeps on every beat, targets that lock onto the high-contrast points the line passes, and the contours with coordinate ticks). AIM moves BOXES' crosshair from the CENTER to the THIRDS points, the FIBONACCI point a golden spiral winds into, or a RANDOM point dealt on every beat; FOLLOW: MOTION anchors on whatever moves, the way a blob tracker boxes motion and leaves a still background alone. AIM SIZE sets how big it is. BOX STYLE draws the boxes as BRACKETS, a FRAME, an X-FRAME, a CROSS running past the edges, a GRID, marching DASHes, a round SCOPE, drifting PARTICLEs or a tinted BACKDROP (BACKDROP COLOR, BACKDROP OPACITY); LABEL STYLE: TAG sets the labels on solid tags. PLEXUS' LINE STYLE draws its links STRAIGHT, as a bowed CURVE, a traveling SNAKE, a jagged LIGHTNING bolt or DASHED (DASH SIZE, GAP SIZE); LINKS: HUB wires every point to the middle of the frame, and CONNECTION RATE thins the web. COLORS: SEPARATE gives the boxes, the plexus and the labels their own colors.
- RANDOMIZE re-deals the looks' choices on EVERY BEAT or EVERY 4 BEATS: the shape of the markers and tiles (square, circle, bracket, cross), how the lines link (nearest, radial, both), the curtain's density, the scan's direction and which looks sit a beat out. The motion keeps running through every switch.
- Two more looks build a printed composition around the subject. GRID breaks the frame into modules, large where the subject is and smaller in the background: MEASURE draws them as a drafting grid, EDITORIAL leaves blank blocks (NEGATIVE SPACE), FRAGMENT refills each module with the picture from a shifted spot, and DATA labels them; MODULE COUNT, CELL VARIATION, SOURCE ADHERENCE, GUTTER and GRID MOTION shape it. GRID FILL writes inside the cells: NUMBERS (each cell's number, large), COORDINATES (each cell's position and size as a data table, with the grid's size and the subject's position), TERMINAL (a scrolling machine log of pings, login attempts and port scans), LOREM (placeholder text that types line by line and scrolls up, or with LOREM MOTION: FLASH, swaps whole paragraphs on the beat) or MIXED (a different fill in each cell). FILL SIZE sets the text size, FILL RATE how fast it scrolls (faster with the music, a slow crawl without it) and FILL DENSITY how many cells are filled. SHAPES puts marks on the most important points (circle, square, diamond, cross, bracket or mixed), a few large and many small (SIZE HIERARCHY), turned along the outline. In PLEXUS, LINKS picks how points join: proximity, a DELAUNAY triangle mesh, an EDGE CHAIN along the outline, radial stars, right-angle ORTHOGONAL elbows or a hybrid, or BANDS, where the music wires it: fans of links from a few points, long ones for the bass, medium for the mids and short quick ones for the highs, each band rewiring on its own hits, with more of the web showing the busier the mids get. When the music stops, BANDS shows the plain proximity web as a preview. LINE CONFIDENCE drops the weak links and LINE WEIGHT thickens them. SCAN's curtain takes a CURTAIN DIRECTION, CURTAIN DENSITY and EXTRUSION LENGTH.
- RHYTHM ties the looks to the music's bands. BASS → SCALE swells tiles, rings, boxes and shapes with the bass, MID → LINKS makes the plexus reach further and keep more of its links with the mids, and HIGH → DETAIL adds boxes and thickens the scan curtain with the highs. SYNC STRENGTH scales all three (0 leaves the looks as they were). BEAT OFFSET moves the beat that re-deals the looks and restarts the sweep, up to a quarter second later, or earlier by firing the next beat ahead of time from the tempo.
- The looks add up. Every look you turn on draws over the others without taking anything away. Under OBJECTS, each object's box gives the looks its corners, edge middles and center to draw on. With no music playing, the looks that are on stay on screen, dimmed to a faint preview, so you can still set them up; they come up to full as soon as the music starts.
- MOTION steadies or shakes what TRACK draws. SMOOTH glides the points between detections so lines stop twitching on a live camera; a still face holds still and a moving hand still follows, and the edges CONTOURS anchors on stop popping in and out. 0 shows the detections as they come, higher glides more (and trails fast moves a little). JITTER does the opposite on purpose: it knocks the points and whole subjects off position, re-dealt JITTER RATE times a second, for a glitch. Put Beat pulse on JITTER and the lines glitch on every kick.
- Every look has its own OPACITY and GLOW in its group, both assignable to the music or a knob: fade the boxes while the scan stays bright, or let only the constellation bloom on the beat. They start at full opacity and no glow, so a look is unchanged until you move them. CONSTELLATION's ring and SCAN's locks label their size as a diameter (Ø).
- TRACK's controls fold into one group per look (BOXES, PLEXUS, CONSTELLATION, MOSAIC, SCAN, LABELS) plus STYLE for intensity, line size, color and RANDOMIZE; a look that is on starts open, so every slider sits under the look it changes.
- LABEL TEXT sets what the labels say: NAMES (what TRACK found and the landmark numbers), HUD WORDS (technical terms such as TRACKING, PROCESSING, CONTOURS, DEPTH and ROTATION, plus the names of the effects you have on, flashing from label to label) or CUSTOM (your own words, typed under CUSTOM WORDS and separated by commas). LABEL RATE sets how fast the words change; with no music playing they slow down. The % beside a box or ring is its size in the frame, so it grows as the subject comes closer, and the DEPTH and ROTATION readouts follow the subject's size and tilt.
- SCAN's parts each have an amount, 0 switching that part off and every one of them assignable to the music or a MIDI knob: SCAN LINE, CURTAIN (with CURTAIN SPECTRUM for how far the hairlines follow the spectrum), TARGETS and SCAN LABELS. SWEEP runs the line ON THE BEAT or STEADY at SWEEP SPEED. A target is born on the scan line, closes in on its point while shrinking onto it and locks there, leaving ECHO trails behind it; TARGET SHAPE picks a HUD TARGET, a circle, triangle, square, diamond or hexagon, or RANDOM for a different one each time. With no music playing the looks slow down and hold still instead of flickering.
- Effects below TRACK in the list process its picture too: FILM GRAIN underneath turns the lines into part of the print. Put EDGES above TRACK, or it traces the lines as well.
- Assign the beat to INTENSITY to flash the lines on every kick, or the bass to LINE SIZE. Above 1, INTENSITY makes the lines glow.
- RENDER includes TRACK over an uploaded video. Use RECORD for a live camera or screen.
How do I hide face outlines or hand and body bones?
Open TRACK → SHOW GUIDES and switch FACE OUTLINES, HAND BONES, or BODY BONES to OFF. Each choice hides its guide lines independently. Tracking, joint markers, rings, and effects that follow the subject keep running. All three start ON; saved looks and rendered videos keep your choices.
How do I open a color window between my hands?
Add HAND FRAME from ADD AN EFFECT, or recall the HAND FRAME look (3 in Performer mode), which loads the TRINA · HANDS demo when no source is selected, with the window and a thin trace over your face and hands in one press. Hold both hands up with the thumbs and index fingers spread, like framing a shot: a window opens between the four fingertips, and inside it the picture turns to moving color. Move your hands to stretch, tilt and close it; it closes when a hand leaves the view.
- PALETTE picks the colors: RAINBOW, or one of the palettes GRADIENT MAP uses. BANDS sets how many times the palette repeats from dark to light, and SPEED how fast it cycles.
- OUTLINE draws a line round the window in OUTLINE COLOR (0 for none), and SOFT EDGE blurs the window's edge.
- SMOOTHING sets how gently the window follows your fingers: 0 jumps to each new position, higher glides.
- Like TRACK, it follows the visual source, or the picture itself when there is none. RENDER preserves it over an uploaded video; use RECORD for a live camera.
For a custom window like this example, add MASK, choose SHAPE: HANDS and AREA: INSIDE, then put GRADIENT MAP, POSTERIZE and ASCII below it. Choose POP in GRADIENT MAP. Keep ASCII's MIX low, and lower TRACK's BOXES OPACITY, PLEXUS OPACITY and CONSTELLATION OPACITY so the colored window stays clear. Read more about masks.
How do I print a window around a face?
Add PORTRAIT WINDOW. A window WINDOW WIDTH by WINDOW HEIGHT of the frame follows the face and prints the picture inside as a HALFTONE (dots grow with the dark, PITCH sets how many) or an ENGRAVEing (lines thicken with the dark, LINES sets how many), in INK on PAPER, or leaves it untouched with NONE. BACKDROP BLUR softens everything outside it and OUTLINE frames it. FOLLOW: CENTER holds it in the middle. Like TRACK, it follows the visual source or the picture itself. RENDER preserves tracking over an uploaded video; use RECORD for a live camera.
How do I play an effect only inside my face or between my hands?
Add MASK and put the effects you want confined below it in the rack: everything under it plays only inside the traced shape, and everything above it still covers the whole frame. SHAPE: FACE follows the outline of your face, HANDS the window between your thumbs and index fingers, the way HAND FRAME opens it, so you can stretch, tilt and twist the window and the effect inside goes with it. PERSON cuts out your whole body, hair and hands included, so AREA: INSIDE plays ASCII or a thermal look only on you and OUTSIDE only behind you (a kaleidoscope around you while you stay yourself); GROW pushes the edge out or pulls it in, and SMOOTHING steadies it. BOXES uses TRACK's boxes, following whatever TRACK's FOLLOW picks; on CONTOURS that is up to BOX COUNT boxes BOX SIZE across, the way blob trackers box what they find. DEAL: EACH gives every box its own effect from the ones below the MASK, EACH · BEAT re-deals them on every beat, REGION shapes each box as a RECTANGLE, CIRCLE, DIAMOND, HEXAGON, RING or HEART (the soft edge, outline and glow follow it), and BLINK drops boxes out at random. Below a MASK on BOXES, ZOOM magnifies each box about its own middle (CENTER: BOX), so a box can show a close-up while its neighbors show X-RAY, INVERT, BLUR or a thermal print. AREA: OUTSIDE turns it round, leaving your face or the window clean while the rest of the frame changes. GROW takes in more around the shape (hair and neck on a face), SOFT EDGE feathers it, OUTLINE draws its edge in OUTLINE COLOR, GLOW blooms that color out around it (GLOW SIZE sets how far), and SMOOTHING steadies it. When the face or a hand leaves, INSIDE fades the effects out and OUTSIDE spreads them over the whole frame. Like TRACK, it follows the visual source or the picture itself. RENDER preserves tracking over an uploaded video; use RECORD for a live camera.
How do I make birds (or sparks, or hearts) fly out of my mouth?
Add EMIT with your camera on under VISUAL SOURCE. FROM: MOUTH pours particles out of your mouth while it is open (WHEN: OPEN / POINTING); HAND pours them from an open hand and FINGERTIP while you point; CENTER sprays from the middle of the frame and works without a camera.
- SHAPE picks BIRDS, SPARKS, HEARTS, BUBBLES, CONFETTI or STARS; COLORS: RAINBOW gives each its own color.
- BIRDS fly off as a flock, like the BIRDS visualizer's: each beats its wings and banks as it turns, nearer birds look bigger, and FLOCK sets how tightly they keep together (0 lets each fly alone).
- RATE is how many start each second, SPEED and DIRECTION where they head, SPREAD how wide the cone opens (1 sprays every way), GRAVITY makes them fall or rise, and GROW makes them get bigger as they fly, as if coming toward you. DEPTH ties them to how near you are: a mouth or hand close to the camera pours bigger, faster particles, and one farther away smaller, slower ones.
- HIT (a MIDI pad, a key or OSC) bursts a flock at once, even with WHEN: HIT ONLY. Every slider takes the music or a MIDI knob.
- For birds that keep flocking after they leave your mouth, use the Birds visualizer's own MOUTH EMITTER instead: its real flock pours out and flies on.
- RENDER can emit from the mouth, hand or fingertip in an uploaded video. Use RECORD for a live camera.
How do I throw lightning between my fingertips?
Add TRACK and turn LIGHTNING on. Bolts strike between what TRACK sees, on the beat, on HIT and at STRIKE RATE: CONNECT: FINGERTIPS links your fingertips, EYES your eyes, EYES TO HANDS your eyes to your hands, CONTOURS the picture's outlines and BOXES TRACK's boxes; AUTO picks from whatever is found. Close points hold a continuous arc. BOLT WIDTH, BOLT GLOW, BOLT JITTER and BOLT COLOR shape the strike.
How do I tie glowing threads to my hands, or send out music notes?
Add EMIT and set SHAPE. THREADS draws glowing puppet strings from FROM (your hand, fingertip, mouth or the middle) through whatever moves, retraced on each beat; THREADS, REACH, THREAD WIDTH and GLOW shape them. NOTES sends music notes out the same way as the other shapes.
How do I know the hand window is ready?
With a hand-shaped MASK or HAND FRAME enabled, the rack shows HAND WINDOW READY when both hands form a clear window. SHOW BOTH HANDS means fewer than two usable hands are detected; OPEN A CLEAR HAND WINDOW means the fingertips form a folded, collapsed, or off-picture shape. TRACKING LOST means no fresh result has arrived.
Open TRACKING DIAGNOSTICS · ADVANCED for the hand count and detection rate. Keep both thumbs and index fingers visible, separate the hands, and use even lighting. The status describes the current picture, not a guarantee that the entire clip will track successfully.
Where do I go next?
Return to the FX Rack overview to choose another task. Compare controls in the effects reference, or follow the rendering guide to save your result.