Designing appropriate simulation and analysis techniques for scientific and engineering disciplines often requires the development of novel computational and visualization tools and methods. Under an ESA research contract on the validation of the Sentinel-3 satellite (monitoring marine environment in coastal zones) we developed parallel Monte-Carlo simulations of radiation transfer. Together with CENIMAT researchers (Materials Science) we developed TOMOgpu, a tool and environment leveraging on GPUs for the characterization of reinforcement population in composite materials, already adopted in unforeseen scenarios, such as paleontology (referred in Nature). Classes of problems arising in some disciplines are complex and combinatory, in particular when discrete domains are involved. We have investigated new probabilistic constraint solving algorithms, relevant for informing decision making in inverse engineering and reliability. A main achievement is the development of CaSPER, a constraint solving tool suite including advanced and efficient propagation techniques.