Systems and methods are provided for etiologic-based breath simulation and/or ventilator test platforms that provide operator-configurable breathing patterns, patient respiratory muscular effort waveform characteristics and patient parameter values. According to one embodiment, multiple respiratory muscle effort waveform specifications, each of which have associated therewith one or more waveform parameters, are provided for use by a breathing effort generator. The waveform specifications include (i) a specification based upon an empirical model that approximates clinically-observed, patient-generated muscle pressures, (ii) a specification based on configurable etiology-driven templates and/or (iii) a specification based on a configurable piecewise trajectory template. A waveform engine of the breathing effort generator is configured in accordance with a selected waveform specification and corresponding waveform parameter values. Finally, the desired breathing pattern is simulated by a lung simulation system based on one or more model parameter values and a respiratory muscle effort waveform generated by the waveform engine.