When are expressions typically generated automatically?

Expressions in Siemens NX are typically generated automatically when features are created. This occurs because the software records parameters and relationships involved in the feature, allowing it to maintain consistency and make updates more efficient. For example, when a user creates a geometric feature like a pad, the dimensions and relevant constraints are automatically turned into expressions. This enables designers to make adjustments to their models easily by changing the values of these expressions, which can update all dependent features accordingly. This automatic generation of expressions is fundamental for parametric modeling, providing a linked system where changes propagate through the design.

In contrast, obtaining information on an object does not involve the creation of expressions; it merely retrieves data without impacting the model's parameters. Similarly, deleting a feature would typically remove its associated expressions and dependencies rather than generating new ones. Selecting an object also does not create expressions but is part of the interaction with the software to manipulate or analyze elements within the design environment.