3. Terms in Gest
3.1. Gesture
A gesture is what Gest produces: an audio rate signal,
typically moving at low frequencies, and designed to be
used to modulate synthesizer parameters like an LFO or
envelope generator would.
3.2. Conductor
A conductor is a phasor signal whose frequency
denotes beats in time. A phasor signal is a periodic
ramp generator going from 0 to 1 over a period of time.
While usually used in computer music to build table look-up
oscillators, phasors are used here as an external clock
signal for Gest. Each ramp period produced by the conductor
signal is interpretted as a beat.
3.3. Phrase
The phrase is the core unit used in Gest. Gestures are
chunked together using phrases in sequence.
3.4. Ramp Tree
The underlying data structure in a phrase is known
as a Ramp Tree. At the top of the tree, a fixed chunk
of time measured in beats is equally divided up by some
arbitary number. From there, the beats can be iteratively
subdivided and glued back together using operations known
as polyramps and monoramps to form a rhythmic structure.
This tree structure is then scaled in a way to form a
continuous line segment.
3.4.1. Polyramps
The polyramp operation takes a single ramp and equally
subdivides it into smaller ramps.
3.4.2. Monoramps
The monoramp operation takes two or more consecutive ramps
and glues them back together to form one ramp. From there,
they can be divided up again into smaller ramps using a
polyramp.
3.5. Targets
A target can be thought of as a breakpoint in a line
segment. When a Ramp Tree is populated for a phrase,
the leaf nodes at the bottom of the tree are capped off
with targets. When the gesture runs, the Ramp Tree is scaled
using these targets.
3.6. Behaviors
A behavior determines the way one target gets to another
target. For example, linear behavior draws a straight line
between the targets. Exponential is an exponential line.
A step just returns the current target.
3.7. Temporal Weight
temporal weight refers to the concept that targets can
create tempo fluctations in the conductor signal, and
can be used as a means to compress and expand rhythmic
phrasing for a lyrical gesture. There are two main
components to temporal weight: mass and inertia. Mass
refers to how fast or slow the tempo becomes, and inertia
refers to the rate at which something responds.
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