Active EO imaging systems are more and more considered as an outstanding solution for detection/recognition or guidance purposes in severe atmospheric conditions such as heavy fogs or in the presence of smoke due to flares in smoke-producing devices. In particular, flash laser systems that have range gating capabilities enable the elimination of photons that are backscattered by the particles in the atmosphere and hence improve the systems detection performances. Range gated systems also offer recognition/identification capabilities based on the target shape identification. Thus it is of great interest to be able to assess the performances of such systems in different operational conditions and simulation is a good means to do this. The SE-Workbench workshop, also called CHORALE (French acceptation for "simulated Optronic Acoustic Radar battlefield") is used by the French DGA to perform multi-sensors simulations. CHORALE enables the user to create virtual and realistic multi spectral 3D scenes, and then generates the physical signal received by a sensor, typically an IR sensor.