  Graph is considered a promising way for managing building information. A new
graphic form of IFC (Industry Foundation Classes) data has just been developed,
referred to as IFC-Graph. However, understanding of IFC-Graph is insufficient,
especially for information query. This study aims to explore graphic building
information query and develop a graph query language tailored for IFC-Graph. A
series of tasks were carried out, including a) investigating the structure of
IFC data and the main types of information in IFC, b) investigating the graph
query language Cypher, and c) developing a set of tailored functional query
patterns. The developed language is referred to as Cypher4BIM. Five IFC models
were used for validation, and the result shows that Cypher4BIM can query
individual instances and complex relations from IFC, such as spatial structure,
space boundary, and space accessibility. This study contributes to applications
that require effective building information query, such as digital twin.
