1. A method of executing a physics simulation in a system comprising a computational platform, a main application stored in the computational platform, a secondary application stored in the computational platform, and a cloth application programming interface (API) implemented in the computational platform, the method comprising: defining a cloth simulation call in the cloth API; by operation of the main application, invoking a software routine using the cloth simulation call; and, by operation of the secondary application, updating a state of the physics simulation in response to the software routine.