Introduction to Paths
A PathInstance (or a Path or PI) is an ordered collection of pitch groups. A pitch group, or a Multiset, is the simultaneous representation of pitch-space, pitch-class space, and set-class information for a collection of microtonally-specified pitches. This collection can be treated as an ordered or unordered collection, can be edited by transposition, replacement, or serial re-ordering, and can be used by one or more Textures to provide pitch materials that are then independently transposed and interpreted by the Texture and its ParameterObjects.
A PathInstance allows the representation of ordered content groups, and presents this representation as a multifaceted object. Paths can be of any length, from one to many Multisets long. A Multiset can be specified in terms of pitch class (excluding octave information with integers from 0 to 11), or in terms of pitch-space (including octave information with integers below 0 or above 11, or with register-specific note names such as C3 and G#12). A Multiset can also be specified as a group, set, or scale sequence such as a Forte set-class (Forte 1973 [AN#161]) or a Xenakis sieve (Ariza 2005 [AN#613]). Finally, Multisets can be derived from spectrums and frequency analysis information provided from the cross-platform audio editor Audacity (enter "help audacity" for more information).
A Path can be developed as a network of intervallic and motivic associations. The interpretation of a Path by a Texture provides access to diverse pitch representations for a variety of musical contexts, and permits numerous Textures to share identical or related pitch information. The use of a Path in a Texture, however, is optional: a Path can function, at a minimum, simply as a referential point in Pitch space from which subsequent Texture transpositions are referenced.