Marble Run Studio

How to play

1. Pick a part. It appears on the open end of your track, already joined. Press Place here (or click/tap the track).
2. Drag a part to move it; it snaps when one of its ends comes near an open end. Turn it with R or the turn buttons.
3. Press ▶ Run (or Space). Watch the marble; Watch replay plays the run again with a follow camera.
4. Change one part and run again. In a challenge, pass the checkpoints in order and let the marble settle in the cup.

Controls

• Mouse: drag empty space to turn the view, scroll to zoom. Drag a part to move it. The round buttons turn, zoom and reset the view.
• Touch: one finger places and moves parts in Build mode; two fingers turn and pinch-zoom. Camera only makes every drag turn the view.
• Keyboard, with the track focused: Space runs and resets, R and Shift+R turn the selected part, arrow keys move it one grid step, Page Up and Page Down raise and lower it, Delete removes it, Ctrl+Z and Ctrl+Y undo and redo, Home resets the view, Escape cancels.

The rules

• Two ends join when they are within 1.5 cm and face each other within 2 degrees; a part that lands nearer than 6 cm without lining up is refused, with the exact misalignment shown.
• Parts may not overlap or go through the table, and must stay within 5 m of the centre.
• Finish: the marble's centre must stay inside the cup, slower than 0.25 m/s, for half a second, after every checkpoint in order. Reaching the cup early shows which checkpoint is missing.
• A marble that falls to the table, leaves the build area or stops for 3 seconds has not finished. Waiting at a gate or a lift does not count as stopping.
• A design holds up to 250 parts and 8 marbles (120 parts and 4 marbles on touch devices).

Scoring, saving and limits

Challenges only: score = 1000 − 5 for each part beyond the reference solution − 10 for each second the marble takes, after a successful run. Best scores are kept on this device and reset when the content version changes. Free building has no score.

Your track is saved in this browser after every change. Download a backup to keep it or move it; importing is checked first and can be undone. Copy track link puts the design in the link; the recipient sees the same parts, though playback can differ slightly between devices.

The 3D view needs WebGL 2 and WebAssembly. Physics is a model: rolling resistance is approximated and the finish cup is felt-lined, so real marbles will differ. A slow device runs the simulation slower rather than skipping steps.

Accessibility

Every part can be placed, moved, turned and removed with buttons, the parts list and numeric fields, and the keyboard works on the focused track. The run itself is visual; the status line reports time, checkpoints and the result in words.

Questions

Why did the marble fly off?

It was going too fast for the bend or the drop before it. Add a straight or a gentler slope before the bend, or use the banked curve.

Why will a part not join?

Its end is close to another end but not lined up. Use Snap to port in the inspector, or move it until the ghost turns green.

Is every challenge solvable?

Yes. Each one shipped with a reference solution that finished under the same physics and rules you play with.