Sketch a top-down path. Nodes connect into one continuous C¹-smooth spline.
Controls
Place — tap empty space to append a node.
Edit — drag a node to move it, or a handle tip to reshape the curve.
Delete — tap a node to remove it.
Slope — a side profile of the descent, shaped as its own bezier curve.
Track
Nodes0
Segments0
3D mode
2D editing is locked here; bank, steepness, resolution, and sampling stay adjustable. Press Play to drop a marble.
Camera
One finger to orbit, two fingers to pan, pinch (or scroll) to zoom. Desktop: WASD flies the camera.
Simulation
Marbles0
Recording
Captures 15 seconds of Box3D's native world-state recording and downloads it. Starts the simulation if it isn't already running.
Bank (twist handles)
With Edit on, tap a red node to reveal its dial, then drag to roll the rails around their own direction of travel — banking a curve so a fast marble gets pushed inward instead of skipping off.
Sampling
Uniform-t (the default) packs more samples into tight curves; arc-length spaces samples evenly by real distance instead.
Resolution32 / segment
Display
Track
Rail vertices0
Collider triangles0
Contact tuning
Lower hertz or higher damping ratio gives a contact more "give" before it pushes back — these two retune the whole physics world, so any marbles in flight reset. Friction and restitution apply per-rail and don't reset anything.