System for Procedurally Generating and Remixing Audio Based on Geometric Representations of Pitch


Audible Geometry (2018-19) is a system for procedurally generating and managing pitched audio, consisting of music or sound effects, based on a virtual listener's traversal of a virtual two- or three-dimensional lattice of pitch nodes. This lattice can be overlaid invisibly on traditional game level design, allowing an in-game character to trigger modulation of key, tonal area or harmonic field based on their traversal of the level. This system thus links modulation of key or harmonic field, a particularly powerful emotive effect, with progression through an explorable space.

Audible Geometry can be applied by remixing music stem tracks, each tuned to a specific pitch class (for instance, all instances of C in any octave), or it can be applied by supplying a pool of currently available pitches to a just-in-time composition system that creates melody and accompaniment from those pitches.

This system is used in Rite of Tephra by Platypus Games. Rite of Tephra is a three-dimensional action-adventure game that features exploration of procedurally generated caves with a grappling hook. The unpredictable nature of the caves and the ability to explore the vertical dimension with the grappling hook allows the user to fully experience the effects of Audible Geometry.