A structure that casts a meaningful shadow, for example, the blade of a sundial or the tip of an obelisk. In the original Greek, "gnomon" (γνώμων) means "one who discerns or examines". When you swing forward on Gnomon, the shadow skull turns to examine you.
What is slotimation?
It's my working name for a method to coax animated images from komorebi-like shadow phenomena.
What is komorebi (木漏れ日)?
The pattern of light made by sunshine filtering through the leaves of a tree.
How does it work?
Instead of a tree, we filter light through two or more perforated panels to produce a pattern of light on the ground. Usually the perforations take the form of variable-width slots; in Gnomon they're cut out of plate aluminum and steel. As the sun (or a panel) moves, the filtration of light changes. We optimize the shape and size of all the perforations so that the filtration continuously morphs through a sequence of images.
How does it produce continuous-tone (a.k.a. grayscale) images?
The sun is a spatially extended light source, so any shadow it produces is slightly blurred. When optimizing the perforation pattern, we exploit solar blurring to mix different amounts of light and shadow, much like mixing black and white paint to produce shades of gray.
Is it related to moiré?
While both are based on interference, moiré is classically understood to be a slightly different phenomenon based on beating -- the perceived interference between two periodic patterns of slightly offset phase or frequency. Slotimation is somewhat more general in that it doesn't presume any periodicity in the layer patterns or target imagery. If you ask for a beating, the slotimation optimization will give you a moiré.
Does it work on cloudy days?
There's no shadow to animate, but Gnomon still entertains: The swings mechanism is also a coupled harmonic oscillator. If you sit passively on one swing and have a friend swing on the other, the mechanism will transfer energy from your friend to you, until you are swinging and she is idled. Then it will transfer it back. On a windless day, the energy can transfer back and forth several times.
Does it scale?
From centimeters to tens of meters.
Older project updates & photos:
TEST of design revision 91
It works! Packed early (due to rains) and ready to ship.
BUILD of design revision 91
Wood is all cut and fitted, currently drying.
Parts for roof mechanism are all machined and assembled.
Night-time lighting rig is done.
Test build in progress!
Remaining: awnings, 2nd imaging plate.
Design revision 91
Stronger roof-to-legs attachment system.
Design revision 90
Beveled of joint between leg & main buttress.
Design revision 89
Shifted slots to simplify build sequence.
Design revision 88
Improved transmission of dynamic loads in YZ plane.
Design revision 87
Small tweaks to facilitate tight packing of cut patterns.
Design revision 86
Added short YZ-plane buttress.
Design revision 85
Replaced tab-and-slot construction with wedge-lock tenons (stronger).
Upper roof replaced with captive sliding tray (more precise, robust).
Added more horizontal braces for torsional stiffness.
