Restorative is a skill in the Physicist skill tree that changes the rotational ability of objects, while still allowing them to move horizontally and vertically (in layman's terms: left, right, up, and down). Much like Architect and its alternate solidity/transparency, repeatedly using Restorative on an object will enable/disable its rotational ability.
Another example is using it to construct an airship. This can be done by placing a plank, using the skill and then using a balloon on it. The amount of balloons will effect the speed.