THE ISOCURVE STEP

Trace the tone. Keep the paths.

Try the full scene ↗

Choose a brightness threshold. The same crossing points become connected contours, then ordinary filled shapes.

Threshold τ 0.45 Tone bands 7 Smooth final paths

01 Sample a fieldGold square: the cell enlarged next.

Samples at or above τ belong inside. A zero border closes curves at the image edge.

02 Interpolate the crossingt is the fraction along the gold edge, from a to b.

t = (τ − a) / (b − a)
Computing the highlighted edge…

03 Stack filled contoursRepeat the construction at several levels.

Bright bands cover dark bands. Compound paths preserve holes; smoothing is optional.

Synthetic light field; real contour extraction. RIVX applies this to sampled splats or render fields, using premultiplied luminance and source colors. This diagram isolates the geometry; it does not render through Rive or export a file.