User Defined Fields (UDFs) are a powerful extension mechanism in the Actenum Decision Support and Optimization (DSO) common model—but without discipline, they can introduce hidden dependencies, performance issues, and technical debt. This session reframes UDFs as a structured extension layer between the core model and downstream metrics, layouts, and scenario comparisons.  

We’ll review common UDF types, when calculated UDFs add real value, and key risks such as circular dependencies, silent expression failures, and performance amplification. The session also addresses a common gap in DSO environments: governance and version control.  

Attendees will learn why maintaining a master template project is critical and how to determine when UDF logic is ready to be promoted into the core model. Participants will leave with practical design patterns and guardrails for building scalable, maintainable UDF ecosystems.