Technique · Fields
Moon jellies
Translucent white jellyfish at different tilts drifting through black water, with glowing rims, radial streaks and four-ringed centres.
Moon jellies 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
- Aurelia aurita has no brain and no heart; a net of nerves around the bell's edge sets the rhythm of its pulse.
- A moon jelly begins as a larva that settles on a rock and becomes a polyp; the polyp then stacks off tiny young jellies, ephyrae, like a pile of saucers.
- The Blaschka family of Dresden, Leopold and his son Rudolf, made glass models of jellyfish and other soft sea animals for museums from the 1860s, because such creatures cannot be preserved in a jar without losing their shape.
- The moon jelly, Aurelia aurita, shows four horseshoe-shaped rings in the middle of its bell: they are its reproductive organs, seen through the transparent body.
- Moon jellies are found in almost every ocean; their sting is too weak to be felt by most people, and they feed on tiny plankton caught in mucus on the edge of the bell.
- A jellyfish is about 95 percent water, and the moon jelly swims by pulsing its bell, one of the most energy-efficient ways of swimming that scientists have measured.
The mathematics
- A disc tilted by an angle t away from the viewer projects to an ellipse whose short axis is R cos t: here each jelly has its own squash between about 0.3 and 1.
- The radial streaks are sin(n times the angle) raised to a power, which sharpens the soft waves into thin lines; the angle is the polar angle round the centre of each disc.
- The 9 jellies are drawn far to near, each dimming what is already there: a painter's algorithm needs no depth buffer when everything is partly transparent.
In art
- White on black reverses the usual drawing: the lines are light, and the darkness around them is the picture's space, as in scratchboard and in white-on-black engravings.
- A bright rim is a standard way for painters to suggest a glassy, translucent edge: the lit edge separates the form from the dark behind it.
More ways to use it
Related techniques
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