The same Biot–Savart kernel that drives the 2D heatmap evaluates a full volumetric H-field on grids up to 100 × 100 × 100. Switch render mode without re-solving — the tensor is shared.
AirInduct Sim visualises the magnetic field of a coil pair as a 3D surface, a heatmap and a contour plot, all drawn from a single solver run. The field is evaluated point by point with the closed-form Biot–Savart law on a regular grid, so the plots show the computed H field itself rather than values interpolated across a FEM mesh. Because every view reads the same result, switching between them is instant and needs no second solve. The 3D surface shows where the field peaks above the coil, the heatmap shows how it spreads across the plane, and contour lines join points of equal strength, which makes uniformity and the edge of the useful coupling area easy to judge. The peak H value is reported alongside mutual inductance M, self-inductances, coupling k and induced voltage, and the field plots travel with the design into the exported PDF report.
Solve once, then move between a 3D surface, a heatmap and contour lines for every field component and the induced voltage. Each view reads the same result, so switching is instant.
The 3d_volume render mode draws nested isosurfaces of |H| so the geometry of the field becomes legible at a glance. Adjust the threshold with a slider; the surface re-meshes against the cached H-tensor without a second solver call.
Underneath every visualisation is a vectorised voxel grid evaluated via Biot–Savart on NumPy. The 2D plane caps at 500 × 500; the 3D volume at 100 × 100 × 100. LOD levels 0 / 1 / 2 cut grid density in halves and quarters for a 4× speed-up.
The vector_field mode overlays downsampled arrow glyphs on the same tensor — direction at a glance, magnitude through opacity. Density factors of 2 to 4 keep the canvas readable on large coils.
Three: a 2D plane heatmap (XY, YZ or XZ slice), a 3D vector field with arrow density control, and volumetric isosurfaces of |H| at user-set thresholds — all driven by the same shared field tensor.
Up to 100 × 100 × 100 (one million sample points) on a modern browser. Switching render modes re-uses the cached tensor — no re-solve required.
For air-core inductive coil pairs, yes. AirInduct Sim renders the field in 3D directly in the browser — no FEM licence, no separate post-processing module — and it is free to start. Fields shaped by ferrite, shielding or nearby metal still need a FEM tool.
