Technique · Fields
Leaf veins
The vein network of a leaf seen close up, with a midrib, curling side veins, cross veins and a fine net lit from behind, or a skeleton leaf of glowing veins alone.
Leaf veins is a field drawn for every pixel by the graphics chip. 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
- Leaf veins are far denser than they look: broad leaves typically have five to ten millimetres of vein in every square millimetre, and flowering plants have denser veins than ferns and conifers, which has been linked to their high rates of photosynthesis.
- The pattern of veins is laid down as the leaf grows, by the plant hormone auxin, which flows through the cells and carves channels in the places where it is most concentrated; the channels become veins, and loops form where the flows meet.
- Veins carry water up into a leaf and sugar out of it; broad leaves of most flowering plants have a net of veins that forms loops, which keeps every part of the leaf supplied if one vein is damaged, while grasses and lilies have parallel veins; in a typical broad leaf there are several millimetres of vein in every square millimetre of leaf, so a leaf the size of a hand holds tens of metres of them.
The mathematics
- Side veins here follow u - |v| tan(a) - c v squared = k s, where u is the distance up the midrib, v the distance across, a the angle, c the curl and s the spacing; the |v| makes the veins on the two sides of the midrib meet it at the same height.
- The net of veinlets is the set of edges of a Voronoi diagram, which is also how a network that grows by filling the largest gap left between its branches comes out; the loops it makes are what let a damaged leaf go on carrying water.
In art
- The net of a leaf is the pattern that engineers copy when they want a light, strong, damage-tolerant sheet, and pressed and skeleton leaves were a Victorian fashion, bleached, mounted and displayed under glass domes.
More ways to use it
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