Working Model 2D

Working
Model 2D is an award-winning motion simulation package that allows
engineers, designers, and animators to build and analyze mechanical
systems quickly on desktop computers. Users can import geometries from
popular CAD systems or draw them in Working Model 2D. Click the Run
button and watch your designs spring to life. Graphs and digital
display tools let you measure standard system variables, or use a
built-in equation language to graph any calculation