Blender - Blender is the open source, cross platform suite of tools for 3D creation.
EcosimPro - EcosimPro is a continuous and discrete modelling and simulation software.
FreeCAD - An open-source parametric 3D modeler
FlexSim - Simulation software to model, simulate, predict, and visualize systems in manufacturing, material handling, healthcare, warehousing, mining, etc.
MATLAB - A high-level language and interactive environment for numerical computation, visualization, and programming
Simio - Facility design simulation & production scheduling