Thing Type

This contains a single Thing in this Space. It can be any Thing: an Instance, a Model, a Property -- even a Type or the Space itself.

When you create or edit a Property of Thing Type, the system will let you Restrict to Model. This is optional, but usually helpful. When you are editing a Thing Property, the system will prompt you with existing Things. If you choose a Model to restrict to, it will only prompt you with existing Instances of that Model. So if you know what sorts of Things you will be using in this Property, it is worth restricting to that Model.