Also in the musical case, we often desire that our models run in real time. That is, we may supply model inputs from a live human performer, and the task of the model becomes rendering high-quality sound based on performance gestures. Real-time computational forms are ubiquitous in the field of digital signal processing, and in large measure, this book is about signal processing methods most applicable to real-time computational physical models.
Physical models are desirable when many dimensions of expressive control are needed. This is generally best appreciated by performing musicians. Audience members only hear the final music played, so they are not in a position to judge the quality of multidimensional control, as skilled musicians utilize only a narrow control subspace in any given performance.2.1