Spectrum simulation is a useful practical and pedagogical tool. Particularly with complex samples or trace constituents, a simulation can help to understand the limits of the technique and how to optimize the tools for the optimal measurement. DTSA-II provides both easy to use and flexible tools for simulating common and less common sample geometries and materials. Analytical models based on φ(ρ z) curves provide quick simulations of simple samples. Monte Carlo models based on electron and x-ray transport provide more sophisticated models of arbitrarily complex samples. DTSA-II provides a broad range of simulation tools in a framework with many different interchangeable physical models. In addition, DTSA-II provides tools for visualizing, comparing, manipulating and quantifying simulated and measured spectra.