  OTTR is a language for representing ontology modeling patterns, which enables
to build ontologies or knowledge bases by instantiating templates. Thereby,
particularities of the ontological representation language are hidden from the
domain experts, and it enables ontology engineers to, to some extent, separate
the processes of deciding about what information to model from deciding about
how to model the information, e.g., which design patterns to use. Certain
decisions can thus be postponed for the benefit of focusing on one of these
processes. To date, only few works on ontology engineering where ontology
templates are applied are described in the literature.
  In this paper, we outline our methodology and report findings from our
ontology engineering activities in the domain of Material Science. In these
activities, OTTR templates play a key role. Our ontology engineering process is
bottom-up, as we begin modeling activities from existing data that is then, via
templates, fed into a knowledge graph, and it is top-down, as we first focus on
which data to model and postpone the decision of how to model the data.
  We find, among other things, that OTTR templates are especially useful as a
means of communication with domain experts. Furthermore, we find that because
OTTR templates encapsulate modeling decisions, the engineering process becomes
flexible, meaning that design decisions can be changed at little cost.
