Interactive application
Interactive
Overview · selected highlights

Circle · Roundness Lab

What should a good circle score actually measure? Draw a contour, separate size from shape, and compare radial error, annulus width, compactness, curvature and harmonics. Counterexamples expose where a convenient aggregate score hides a visible defect.

A familiar shape; competing definitions
DrawMeasureCompare
Brochure →Open project ↗
  1. ∮

    Capture the stroke

    Keep the original contour and make any accepted closure explicit.

  2. s

    Normalize the shape

    Resample by arc length and separate scale from dimensionless error.

  3. κ

    Inspect the signals

    Compare several geometric measurements instead of one opaque score.

  4. Δ

    Challenge the policy

    Change aggregation and test defects, smoothing and size sensitivity.

A reproducible score needs declared geometric choices; roundness and capture quality are separate questions.

The same dented contour at radii 100 and 8. The illustrative absolute-error score rises when the shape shrinks, while the normalized geometric score stays at 31.2. This baseline is a teaching model, not a measured score from another game.
The same dented contour at radii 100 and 8. The illustrative absolute-error score rises when the shape shrinks, while the normalized geometric score stays at 31.2. This baseline is a teaching model, not a measured score from another game.