This class represents the type of data object that the container SimDM/Protocol can produce. 
This concept includes any type of data object the protocol deals with.
It can range from the smallest data units such as individual N-Body particles or pixels in a synthetic spectrum, up to the largest which may be a collection of snapshots in an N-body simulation ,each of them containing collections of particles.
It defines also the actual SimDM/OutputDataset-s that a SimDM/Experiment's has produced. 
Since a SimDM/OutputDataObjectType is-a SimDM/ObjectType, it can be related to other objects using SimDM/Relationship-s.
 In this way a hierarchy of data types can be described.
For example a spectrum can be a such a data object and will be composed of pixels. A FOF group catalogue will be composed of FOF groups which are aggregations of particles. 