How to Make a Ball Bounce to Any Song
Pick or upload a song, sync the bounces to it, clean up the melody and record. The workflow behind "the ball plays a song" videos.
How the Ball Plays a Song
In Rhythmic mode the song is a queue of notes. Every time the ball hits the wall, the engine plays the next note and moves on. It never guesses a pitch from the impact, so the tune stays recognisable however wild the physics get: the order is fixed, only the timing is physical. With Music sync on, the engine also steers the ball so each hit lands exactly when the next note is due.
Key tips
- Pick Rhythmic in Basics under Simulation type. It is the best mode for this whole tutorial.
Step 1: Choose the Track
Open the track picker in Basics > Sound (or Audio on the rail). The Song Library is a shared set of 1,000 original songs written for BallEngine, all safe to monetize and open on every plan, and it is the quickest way to a clean result. To use a specific song, you have two routes. A MIDI file carries the real notes, so every bounce lands on a true note of the piece. An audio file (MP3 or WAV) has no note data, so the Studio slices it instead and each bounce plays the next slice. MIDI gives the cleaner result.
Key tips
- Search for the song name plus "midi" and prefer a single-instrument arrangement over a dense multi-track one.
- Uploading your own MIDI is included with Creator and up. Uploads are limited to 10 MB per file.
Step 2: Upload and Make It Active
Use Upload MIDI or Song inside the track picker. The file becomes the active track straight away and the run restarts. Everything you upload also appears in the Media library inside Audio > Sound, MIDI & audio hub, stored with your account so it follows you to any device. Press Reset and sync under the picker whenever you change the track, so the song and the ball start together.
Step 3: Turn On Music Sync
Music sync is an add-on under the mode picker in Basics. On, the ball bounces on the beat and the song keeps its real tempo. Off, the ball bounces with normal physics and still plays the next note on each hit, which sounds looser but looks more natural. For "the ball plays a song", leave it on.
Step 4: Cut the Song Down to the Hook
A full song is longer than a short clip needs, and a dense MIDI fires more notes than the ball has bounces. Audio > Sound, MIDI & audio hub has the tools to fix both: MIDI bounce filtering decides which notes make the ball bounce (and can skip a long intro), and the MIDI editor lets you trim and edit notes. Viewers should recognise the song in the first two seconds, so start at the hook, not the intro.
Key tips
- If the melody sounds crowded, filter out the lowest track first. Bass lines rarely help a bounce mapping.
Step 5: Stop the Melody From Racing Ahead
The most common problem is tiny rattling contacts firing extra notes. In Engine > Rhythmic mode settings (Creator and up), raise Min bounce spacing (ms), from 0 to 1000: it sets the shortest gap between two sounding bounces, and 80 to 200 ms collapses a rattle into one note. Playback speed (0.1x to 4x) fits the piece into your clip length, and Sync offset (-500 to 500 ms) nudges the picture against the sound. Play original song lays the source track under the bounce notes, which thickens a thin melody.
Step 6: Record
Set the clip length in the top bar, press Restart and watch one full run, then press Record. The export is timed frame by frame, so a clip that drifted in a stuttering preview is usually on the beat in the finished video.
Key tips
- Want the ball to break out through rings while it plays? Turn on the Breaking rings add-on: that is Rhythmic Escape. See the Rhythmic Escape guide in Help.