16.6 Issues with Virtual Preschool Engineering 301 | P| Se, A ” - Fig. 16.2: Part 2 of a Piagetan conservation of volume experiment: a child observes two different- shaped glasses, which (depending on the level of his cognition), he may be able to infer have the same amount of milk in them, due to the events depicted in Figure 16.1. 16.6.1 Integrating Virtual Worlds with Robot Simulators One glaring deficit in current virtual world platforms is the lack of flexibility in terms of tool use. In most of these systems today, an avatar can pick up or utilize an object, or two objects can interact, only in specific, pre-programmed ways. For instance, an avatar might be able to pick up a virtual screwdriver only by the handle, rather than by pinching the blade betwen its fingers. This places severe limits on creative use of tools, which is absolutely critical in a preschool context. The solution to this problem is clear: adapt existing generalized physics engines to mediate avatar-object and object-object interactions. This would require more computation than current approaches, but not more than is feasible in a research context. One way to achieve this goal would be to integrate a robot simulator with a virtual world or game engine, for instance to modify the OpenSim (opensimulator.org) virtual world to use the Gazebo (playerstage.sourceforge.net) robot simulator in place of its current physics engine. While tractable, such a project would require considerable software engineering effort. 16.6.2 BlocksNBeads World Another glaring deficit in current virtual world platforms is their inability to model physical phenomena besides rigid objects with any sophistication. In this section we propose a potential HOUSE_OVERSIGHT_013217