Drag the spheres to reshape the wire · double-click the wire to add a point · Del removes the selected point · left-drag orbits, wheel zooms. The cyan sphere is a field probe. Arrows & slice color show |B| on a log scale.

Magnetic field of a line conductor

Live Biot–Savart integration — sculpt the wire and watch B(r) react.

Conductor

Closed loop (connect ends)

Current

Reverse current direction

Field slice

Show |B| heat slice

Plane

Offset

low |B|high |B| (log)

Field arrows

Show B vectors on slice

Density

Probe line · 2D graphs

Axis

Overlay |B| (rescaled)

View

Auto-rotate camera

B(r) = (μ₀/4π) I ∮ dl×r̂/r², integrated numerically over the wire. Distances in metres, field shown in µT. Requires internet once to load Three.js from CDN.