Frame

A frame is the work area and the "scene": shapes, physics and variables live inside it. Everything in a frame follows its gravity and scale.

How to add

Use the Frame tool (key F) and drag a rectangle on the canvas. Shapes dropped inside become its children.

Clip content: Anything outside the frame bounds is hidden.
Gravity g and wind gx: Free-fall acceleration (9.81 m/s² by default) and a sideways force for physics inside the frame.
Pixels per metre: Physics scale: how many canvas pixels make 1 metre. Speeds, forces and labels depend on it.
Scale ruler: Draws a ruler in the corner so real sizes are visible.
Variables: Named values with label, unit, min, max and step. Sliders appear over the scene and any object property can be bound to a variable with a formula.
Task: Statement, answer field and check: this turns a frame into an interactive problem.
Auto layout: Arranges children in a row or column with gap, padding and alignment.
Prototype: An action on click, hover or after a delay: go to another frame, go back, start physics.
Run: Starts physics for this frame only.

Keep physics objects inside the frame: there is no gravity outside it.
To build a problem, set the scale first (pixels per metre), then add variables and bindings.