Definition:
Systems can at times be a complex topic with challenging ideas. To better support this, here are some key terms that define the essential concepts around Systems.
For each of the terms, we have highlighted each term in a 3D model of a ventilation unit.
System
A System is not a physical object, but an entity that connects two or more physical Components together.
In the example, the ventilation Components (duct, air diffusers, etc.) are highlighted, but the air handling unit is not because it is a System Component and not part of the System.
Systems can only be owned by one System Components, but can be added to several System Components. It is not required but recommended that the Systems is connected to a system components.
Item and Occurrences
Everything in the Systems Module is built around Items. An Item that has been placed in a project is known as an Occurrence. An Item can have several Occurrences, and multiple Occurrences can be placed in multiple Systems.
In BIM terms, an Item can be equated to a 'Type' and an Occurrence can be equated to an 'Instance'.
In the example model, each Occurrence of the Air Diffusers are highlighted as a single Item.
Component
A Component is an Occurrence of an Item that has been connected to a System.
Outside of the Systems Module, Item Occurrences in dRofus are typically associated with a Room. A Component does not need to be planned in a Room which allows dRofus to capture all objects in the model, not just the room-centric objects.
In the example model, an Occurrence of an Air Diffuser is highlighted as a single Component.
System Component
A System Component is an Occurrence of an Item that owns and defines one or more Systems.
In the example model, the Air Handling unit is highlighted. This is connected to the Ventilation System as well as being powered by the Electrical System and supplied with water from the Plumbing System.
System Components may get their number from a classification, or they can get their number from the Item they are an occurrence of.
Product
Product is the product specific Type you eventually purchase from a vendor. Will contain product data and be attached to the Items. An Item can have several Products connected so you can allocate different Products to different Occurrences of the same Item.
Classifications
National or international standard that describes codes that are human readable once you become familiar with the codes (Omniclass, Uniclass)
Utilizing a Classification System is highly encouraged in the dRofus Systems Module. It can be one of the previously referenced standards or can be a custom classification that is created in or imported into dRofus.
System Hierarchy
In BIM and in real life, 'System Components' can have many systems, but they are also components cross domain and can be connected to other systems.
An air handling unit is normally a system component as it will be the owner of systems as:
Supply air
Return air
Air supply
Exhaust
However, the air handling unit can also be a component in an electrical system as it needs power supply from a electrical circuit. This graph of connections can be viewed hierarchically in the Systems module.
In the image below we are looking at the electrical domain and can see that the Air handling unit is connected to a Main power panel through a sub panel. By looking at the properties to the right we can also see that the Air handling unit is the system component for Supply air, Return Air, Exhaust air, and fresh supply air.
