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Tunnels effect

Gravity Feedback

Gravity Feedback is a tunnel and feedback effect in FRCTL, the browser VJ studio. Last frame swells, spins and drifts back through itself until the picture starts generating its own.

Runs live on video, images, a camera or generated art. Stack it with any other effect, and route LFOs, envelopes or any of ten audio bands to its controls so it moves with the music.

Try Gravity Feedback free All effects

The untouched demo art: an eye inside a triangle over wavy teal, blue and peach lines — Source

The eye-in-triangle with rainbow oil-film fringes running along every wavy line over a dark violet ground — Gravity Feedback, default settings

What Gravity Feedback does

Feeds the last frame back in, scaled by Zoom, turned by Rotate and nudged by Drift X and Drift Y, so the picture streams out of itself in a spiral. Hue warp shifts colour slightly on every pass, which compounds into rainbow fringes along each edge. Sustain sets how long trails hold, and Bloom past halfway lets the loop grow patterns of its own.

Using Gravity Feedback

Where it works: Long set visuals where one still has to carry several minutes, since the loop keeps inventing new structure, and cover art with a burnt-in, oil-film edge. It only works last in the stack, the slot that writes the buffer it reads.
With the music: Doesn't react to audio by itself. Route B2 (sub bass) to Zoom so the frame surges outward on bass notes and settles between them, and a beat-synced LFO on Rotate swings the spiral back and forth each bar.
Starting point: Zoom just above centre, Rotate just above centre, Drift X and Drift Y centre, Sustain centre, Bloom a quarter, Overflow on Clamp.

Controls

Zoom: How much the held frame swells or shrinks each pass. Centre is still.
Rotate: Spin per pass. Combined with zoom this is what makes the spiral.
Drift X: Sideways travel per pass, which throws the spiral off centre.
Drift Y: Vertical travel per pass.
Sustain: How long trails hold. High enough and they stop fading at all.
Bloom: Gain inside the loop. Past halfway the feedback sustains itself into reaction-diffusion.
Hue warp: Hue bend per pass. Tiny amounts walk the whole wheel over a second of feedback.
Overflow: What happens to signal driven past white.

Pairs well with Gravity Feedback