Hopsan is a free multi-domain system simulation tool
Physically accurate and validated GPU ray-tracer
FEATool Multiphysics is an easy-to-use FEA and CFD Simulation Toolbox
A framework for simulating open quantum dynamics
A multi-modeling and simulation environment to study complex systems
Multiagent simulator of road traffic in Qt/C++ and OpenStreetMap.
NeuralSyns is a neural simulator for large spiking networks.
Acoustic Simulation Library for Frequency and Time Domain Simulations.
Multiscale Neuroscience and Systems Biology Simulator
Physics Game like "The Incredible Machine"
A Library for Interactive Modelling and Visualisation
Agent-based framework for Artificial Life and Complex Systems
a Parameterizable Simulator for Early Exploration of Networks On-Chip
Basic real-time simulation engine in C++