freeCAD	A fully functional free Dynamic Simulation Software. Mechanisms are represented by connected or assembled joints of 3D solids with defined constraints, actuators, springs, dampers or forces. In addition to pure geometric and connection information, mass, moment of inertia, gravity, force and torque information are also modeled and used to predict the motion according to Newton's Laws. Animation using the simulated data produces realistic dynamic behaviour of the system under study. @1MB Created by: Aik-Siong Koh. Screenshot
Watt	A refreshing approach to Mechanism Design courtesy Heron Technologies, which rather than analyzing an existing mechanism, can be used to create mechanisms based on required co-ordinate movement, constraints on pivot locations, transmission coefficients, accelerations, dimensions etc. An excellent program that offers solutions to user specifications rather as against the old painful approach of trying to find out the right mechanism that works. Very easy to use friendly Windows interface, however the "Save" is crippled. @1.3MB Created by Heron Technologies Screen Shot
MBDyn	Command line free multi-body dynamics solver. A free graphical user interface can be download from OSEngineer Created by University Politecnico di Milano, Italy
Universal Mechanism	Simulation of kinematics and dynamics of planar and spatial mechanical systems. Mechanical systems are described by means of representing them as systems of rigid bodies connected by various kinematical pairs and force elements (multibody systems). Online animation of motion and plots of dynamical performances are available during simulation. There are lots of measurable dynamical performances of mechanical systems: linear and angular coordinates, velocities and accelerations, active forces and moments, reaction forces etc. Created by: Universal Mechanism Screen Shot