The marble race maker where the output is the video

Every other marble race tool gives you a race and leaves the video to you - screen record, crop, sync, export. RaceCut is built backwards from the post button: you drop a song and a cast, and what comes out is a finished, vertical, 60fps MP4 where whoever’s leading is singing. Ready for TikTok, Shorts and Reels.

How it works

1. Pick a race format. Classic Marble Race (cast of marbles, camera on the leader), Musical Path (one ball descending a corridor composed from the beat), Loop Path (a lap that loops perfectly), or Bounce Battles (two fighters; whoever holds the mic sings). New formats ship regularly - subscribers get them first.
2. Cast your racers. Names, colours, even faces and your own logo on the course. Names are the difference between a video that gets watched and one that gets argued about in the comments.
3. Drop a song. RaceCut listens to it - beat detection finds the drops and bright sections, and the course is composed so the action lands on the music. Pick the exact 15/30/60-second window on a waveform; the chorus usually wins.
4. Give the marbles voices. Each racer gets an AI voice from a catalogue of thousands of characters. The leader sings; hand-offs happen on the exact frame of each overtake. (Why we built it this way: Why the leading marble sings.)
5. Press Race it. A real physics simulation runs, then your device renders 1080×1920 at 60fps and encodes H.264+AAC - about 10 seconds on a laptop, a couple of minutes on a phone, no servers involved. Download and post.

What makes it different from a marble race game

Games and sandboxes - Algodoo, mobile track builders, Roblox creators - are built for playing. Getting a postable video out of them means screen recording, cropping to vertical, syncing music by hand, and an editor pass. That pipeline is hours per video and it shows: most people quit after two. RaceCut collapses the pipeline because the renderer, the music sync and the format are one system. The camera follows the leader automatically, the race is choreographed to your audio, and the export needs no editing whatsoever. If you want a sandbox, we’ll happily point you to the alternatives in our comparison of all six ways to make these videos. If you want the video, you’re home.

Fair races, rigged races - both real

Every RaceCut race is a deterministic physics simulation from a seed (the engine underneath is the same class used in games - details on the simulator page). Leave it fair and the outcome is genuinely unknown until the marbles decide it. Or pick your winner: RaceCut re-simulates seeds until it finds an honest run where your pick takes it. Nothing is keyframed, nothing fakes physics - which is why rigged races survive frame-by-frame scrutiny from twelve-year-olds, the internet’s harshest auditors.

Built for posting daily

• Fresh seed every render - the same song and cast produce a new race every time, so daily posting never repeats (that’s the generator half of the product)
• 15 / 30 / 60-second lengths - the durations short-form algorithms actually favour
• 1080×1920 · 60fps · H.264 + AAC - plays correctly on every platform, including Safari/iPhone
• Your logo on the course, custom styles and palettes per format
• Auto-captions - transcribe the lyrics on your device and burn them in (desktop)
• Works on phones - the studio, the voices and the render all run in the mobile browser

FAQ