Figures and annotations
The Annotate tab adds the elements of a textbook figure. Annotations are part of the scene: they are saved with it, drawn in every export, and those placed on a body follow it while it moves.
The figure elements
| Tool | How |
|---|---|
| Label | click a body (the label follows it) or empty space; type its text in Properties. Notation → Show a value makes it read m₁ = 2.00 kg or v = 1.25 m/s: a value of its body, live while the scene runs |
| Dimension | click two points: on a ground, the point of its surface; on a body, its centre, a corner, the middle of a side, or a face (near the outline); they follow their bodies. Optional dashed extension lines. Properties → Measures: the distance, or only the horizontal or the vertical (a height above the ground) |
| Frame | a pair of axes (e₁, e₂) with a name: inertial, or fixed to a body and turning with it |
| Angle | click a body's corner to mark its angle at once, or click a vertex and a point on each ray. The arc, the arrow heads and the value in degrees are options |
| Centre Line | a dash-dot line between two points |
| Gravity | one click: the ↓ g sign, pointing along the scene's gravity |
| Strobe | click a body: copies of it at equal times through the recorded run (t₀, t₁, …), fading — the multiple-exposure figure. Start, end and count in Properties |
| Gear Figures | Bevel Gears or Worm Drive, drawn side on as in machine-design texts, with their teeth and speed ratio. Bevel gears are cone-shaped gears that turn a shaft round a corner (a hand drill, a car's differential); a worm drive is a screw turning a toothed wheel, a big slow-down in one step (a winch, a guitar's tuning pegs). They are drawings for figures and worksheets and do not move: these gears work in 3D, and the studio simulates flat (2D) motion. Spur gears, racks, ring gears and chains are simulated (Build → Gear). Teeth (or worm starts), size, angle, centre lines and labels in Properties |
Annotate → Clear All removes every annotation.
Writing labels
m_1is drawn m₁,v_{max}^2as a sub- and superscript,thetastays a word butθis the Greek letter. Labels are set in italics, like symbols in a textbook.- A label with a LaTeX command or a
$…$pair is typeset by LaTeX rules:\ddot{x}_1,\frac{L}{2},\vec{r}_{P/O},Pulley $B$. Export → LaTeX Labels typesets every label that way. What you see is what the TikZ export writes. - A label that would run commands in LaTeX (
\input,\write18…) is kept as plain text, so a scene from someone else cannot do anything to your computer when you compile it.
Trails and tracks
Analyze → Track Selected records the selected body's path; Fading Trail draws recent paths fading out (its length is in the scene's Properties → Overlays). Both appear in SVG and TikZ exports.
Textbook style
In Research the scene is drawn as a figure: thin black outlines, hatched grounds, pins as small circles, springs as coils, cables and belts as lines. The screen and every export use the same drawing code, so the SVG, PDF, TikZ and PNG look like what you see.
Presenter mode can reveal annotations one step at a time during a lecture: see Presenter mode. Free-body diagrams have their own page: Free-body diagrams.