There are 115 object types within AI2-THOR. Each object type has a set of Actionable Properties, Material Properties, and Location (within a scene category) associated with them. Actionable Properties are properties that can be directly manipulated via specific Actions defined in the Actions section of the Documentation. Material Properties are reported in Object Metadata, but do not necessarily have an action that can directly manipulate the property. Object Locations are categorized under Scene Categories, as not all objects are guaranteed to be found in every type of Scene.