An integrated optics, controls, and structures modeling tool has been developed to analyze the performance of complex electro- optical (EO) sensing systems. Hosted within an object-oriented graphical environment (Khoros) developed by the University of New Mexico, complex systems such as active ground-based telescopes, airborne spectrometers, and space-based sparse array telescopes can be simulated and rapidly evaluated. The TAOS model integrates data products from existing codes such as MATLAB, CODE 5, NASTRAN, and others to allow multi-disiplinary parametric analysis of system performance. Because the model includes accurate physical optics and radiometric representations, almost any function of an optics system can be quickly generated and studied. In addition, degrading effects of dynamic structures, use of compensating control systems, and effects of the observing environment (wind load, boundary layer, and seeing) can also be included. Use of this simulation tool on NASA programs such as the Space Telescope Imaging Spectrometer has reduced design schedules by factors of three. Other typical analysis applications include the study of atmospheric compensated imaging systems using combined adaptive optics/post-processing techniques, simulation of hyper-spectral imagers, and methods for achieving coherent phasing of telescope arrays. This paper also provides a progress report on TAOS modeling of the European Southern Observatory (ESO) Very Large Telescope (VLT).