This document specifies digital twin compositions in manufacturing by defining principles, describing methodologies and providing use-case examples of digital twin communication, aggregation and interoperation.

This document identifies three kinds of digital twin composition (integrated, unified, and federated) and specifies requirements and step-by-step implementation guidelines for each kind. It provides structured approaches for composing multiple digital twins to support interoperability among digital twins developed by different parties, such as vendors, solution providers, and in-house developers. The document also includes illustrative use cases to demonstrate the practical application of the specified composition approaches.