Mental model — The script contract
We will organize the program as if it were an engineering function:
INPUTS → CHECKS → MODEL → SOLUTION → RESULTS
This separates four categories that should not be confused:
| Category | Example | So, who controls it? |
|---|---|---|
| Entry | beam_h | User or studio |
| Derivative | inertia | Program Expression |
| Reference | uy_ref | analytical model |
| Result FEA | uy_tip | Solver and post-processing |
An analytical reference is not “the correct result” by decree. It's an independent comparison, based on different hypotheses, which helps detect unit errors, loads or stiffness.