Many simulation packages are built on out-dated 2D technology that limits your ability to visualize your process or capture 3D spatial relationships in your system. Some of these older products limit you to 2D only models, while others offer expensive/complex 3D add-ons that require you to build a separate 3D visualization of your system, and then tie these two separate components together. These extra steps add unnecessary work and time to your project, and make your model and animation difficult to edit and maintain. 

In contrast, Simio provides a true object-based 3D modeling environment which lets you construct your 3D model in a single step from a top-down 2D view, and then instantly switch to a 3D view of your system. You simply drag and place your 3D objects from an Object Library into your facility view of the model. 

All Simio model-building products directly integrate with Google Warehouse to allow you to quickly download from a massive library of freely available 3D symbols to easily and quickly add realism to your models.

More info.