An apparatus configured to display a three-dimensional representation of a waveform for a breathing assistance system may include a processor and a display device. The processor may be configured to receive signals from one or more sensors over a plurality of time periods and generate multiple instances of a waveform based on the received signals, each instance corresponding to one of the plurality of time periods. The display device may be configured to cooperate with the processor to display a graphical three-dimensional representation of the waveform over time. The three-dimensional representation may include graphical representations of the multiple instances of the waveform displayed simultaneously.