An asset is a template from which things in the game world are made. An asset instance is an object with a unique ID number, created from an asset.
A material is a set of textures with defined roles (such as diffuse, normal/specular and macro) and associated properties. A material instance a unique combination of material properties which can be applied to one or more asset instances.
Areas are mainly populated with asset instances instantiated from the Asset Library. Each asset instance is owned by one or more rooms (which are persisted in the server GOM and in DAT files) and Prop buckets (not persisted and do not exist in the server GOM. Prop buckets are added and removed through script.) Material Instance Properties can be customized using the Material Instance Properties panel.