How can you tell which reference set is displayed?

The ability to identify which reference set is displayed in Siemens NX comes primarily from the Assembly Navigator. This tool provides a structured outline of all the components and their associated reference sets within an assembly. When working with assemblies, the Assembly Navigator allows you to see not just the components, but also the specific settings related to how they are displayed, including the active reference set.

By looking at the Assembly Navigator, users can quickly determine which reference sets are currently active for each component, ensuring accurate management of visibility and representation of the model's parts. This information is pivotal for managing complex assemblies, facilitating easier navigation and modifications by highlighting the relevant reference set.

Other tools like the Part Navigator or model options also contain valuable information, but they don't specifically focus on the assembly context where reference sets play a critical role in managing the visibility and relationships between components. The graphics window provides a visual representation but does not explicitly state which reference set is active. Hence, the Assembly Navigator is the most appropriate choice for this task.