  Ongoing standardization in Industry 4.0 supports tool vendor neutral
representations of Piping and Instrumentation diagrams as well as 3D pipe
routing. However, a complete digital plant model requires combining these two
representations. 3D pipe routing information is essential for building any
accurate first-principles process simulation model. Piping and instrumentation
diagrams are the primary source for control loops. In order to automatically
integrate these information sources to a unified digital plant model, it is
necessary to develop algorithms for identifying corresponding elements such as
tanks and pumps from piping and instrumentation diagrams and 3D CAD models. One
approach is to raise these two information sources to a common level of
abstraction and to match them at this level of abstraction. Graph matching is a
potential technique for this purpose. This article focuses on automatic
generation of the graphs as a prerequisite to graph matching. Algorithms for
this purpose are proposed and validated with a case study. The paper concludes
with a discussion of further research needed to reprocess the generated graphs
in order to enable effective matching.
