The use of mathematical algorithms to imitate the sounds of accoustic instruments or other physical objects. The theory behind physical modelling was developed in the early 1970s, but it had to wait until faster computers and inexpensive DSP circuits to be developed before it became a practical method of synthesis. Yamaha developed hardware and software for physical modelling synthesis starting in the late 1980s, but its first commercial product based on this research, the VL1, was not introduced until 1994 — just as the fad for realism in synthesis was dying out. Although Yamaha introduced several subsequent products based on this work, none of them sold well. As a result, the potential of physical modelling remains largely unexplored outside of academic electronic music. Physical modelling can do far more then merely imitate accoustic instruments; by mixing and matching different algorithms, sounds which are quite unlike either conventional instruments or subtractive synthesis can be produced.

Roland included physical models in its next-generation Jupiter series, starting with the Jupiter-80 in 2011. However, early versions of the operating system exposed few of the physical modeling parameters to the user, as Roland regarded much of the algorithmic information as proprietary. Subsequent OS revs, and subsequent models in the model series, have alleviated that somewhat.

Current versions of Csound include a number of physical modelling algorithms.