General Mission Analysis Tool
Physically accurate and validated GPU ray-tracer
ASALI is an open-source code for chemical engineers
FEATool Multiphysics is an easy-to-use FEA and CFD Simulation Toolbox
slab3d is a real-time virtual acoustic environment.
Matlab interface to the Open Dynamics Engine (ODE)
collection of illustrative programs:small games, simulators: C, Matlab