4.7.2 What happens when a calculation uses data an element doesn’t have?

Nothing. The result of any calculation involving non-existent data is always voided, to the result will be zero for quantity calculations or false for recipe rules.

This is a deliberate design decision to allow expressions to be created and added in template form to serve a wide variety of projects, even when some of the data, parameters, attributes, properties or classifications don’t currently exist.

Calculations or rules that could never work are immediately flagged up as an error when they are entered. Naming errors, e.g. for materials or parameters, that cause rules or calculations to have no effect should be picked up when the auditing processes are used (see section 6).

This list will be extended to include all future common support questions.