Technique · Geometry
Ridgelines
Stacked profile lines that hide the ones behind them: a pulsar plot, mountains, or interfering waves.
Ridgelines is drawn geometry, rebuilt as it changes. Every piece on Synapse Drip is made from a recipe that layers techniques like this one, and you can change any of it in the Studio.
Good to know
- The first pulsar was found by Jocelyn Bell Burnell in 1967; the fastest known spins more than 700 times a second.
- Hidden-line removal was one of the first problems of computer graphics: Larry Roberts solved it for his 1963 thesis.
- This plot comes from radio astronomy: in 1970 Harold Craft plotted 100 pulses from the pulsar CP 1919 for his PhD at Cornell, and Peter Saville used the picture on Joy Division's 1979 album Unknown Pleasures.
The mathematics
- Keeping the highest line seen so far at every column makes hiding cost one comparison per column per row, so 62 rows are cheap.
- A crossing is found by interpolating between two columns where the new line rises above the old one, so the lines meet exactly, with no jagged cuts.
In art
- When every mark is a single stroke of ink, hiding is the only kind of shading there is; pen-plotter art lives in that limit.
- Peter Saville printed the plot white on black for the cover, and it became one of the most reproduced images in music.
More ways to use it
Related techniques
L-system · Space colonisation · Diffusion-limited aggregation · Flow ribbons · Curve families · Streamlines · Paint strokes · Stipple and Delaunay portrait