The report describes what has been accomplished on vehicle modelling during 2006 in project "Optical Signature Analysis". IR target signature prediction software continuously keeps developing. More phenomena can be physically correctly simulated. Credible target signatures are important for assessment of platform concept development - i.e. develop with low observable signatures from construction. Target signatures can also support operator training and be used for target algorithm development, mission planning and situation awareness (when coupled to TAWS software for example). The main focus for the report is: o New features on dynamic engine and drivetrain modelling have been developed, tested and implemented. o New coupled RadThermIR and CFD++ computations have been demonstrated and presented during ITBM&S conference. o A first step towards validating the engine and drivetrain modelling versus field trials has been performed. The new developed CFD++ and RadThermIR coupling demonstrated that convective heat sources can be really hard to model without volume flow data. The engine and drivetrain modelling including validation will be reported in a separate technical report, some results will be presented here. Different validation approaches will be discussed. Software that can be coupled to RadThermIR, such as CFD++, TAWS, Cameo-Sim and EWSim will also be mentioned.