This video demonstrates how to integrate a Mathcad worksheet with a Flownex simulation, allowing engineering calculations performed in Mathcad to interact directly with system models. Using a simple pipe network example, the tutorial shows how simulation time can be passed from Flownex to Mathcad, where a sinusoidal pressure signal is calculated and returned to the simulation as a boundary condition. The process involves adding a Mathcad Worksheet component, defining input and output variables, and connecting them using Flownex data transfer links. During the simulation, Mathcad continuously updates its calculations while Flownex uses the returned values to solve the network and display the resulting system response. The example highlights the simplicity and flexibility of the Mathcad link, enabling engineers to combine custom calculations with dynamic system simulations.