gbXML is a hierarchy architecture made up of elements and attributes. Elements can have sub-elements, and attributes can help define the features of elements. Some attributes are necessary for building an element. For example, the gbXML tag, locating at the highest-level in the schema, must contain a campus element. Attributes of temperature unit and area unit are required to define the gbXML tag.
Elements are components of a system. For example, Variable Air Volume (VAV) boxes are common components of a typical HVAC system. Defining a VAV box needs both the "HydronicLoop" tag and the "AirLoop" tag under the gbXML tag.
Attributes can help define the specialty of an element.
"Green Building XML (gbXML) Schema". Retrieved November 14, 2020. https://gbxml.org/ ↩
"Software that Supports gbXML". Retrieved November 14, 2020. https://gbxml.org/Software_Tools_that_Support_GreenBuildingXML_gbXML ↩
"Green Building Studio Website". https://gbs.autodesk.com/GBS/ ↩