# SCX Design Assurance and Interoperability Guide

## Purpose

The Design Assurance Workbench connects the canonical crane project to four deterministic server-side capabilities: verified calculations, constraints-based planning, multi-objective optimisation, and CAD/BIM data exchange. Open it from the landing page or at `http://127.0.0.1:8840/scx_design_assurance_workbench.html`.

## Recommended workflow

1. Create or load the layout, crane assets and movement demand in the planning tools.
2. Open the Canonical Project Model Manager and resolve critical identity, relationship, geometry and SWL findings.
3. Open the Design Assurance Workbench and select **Load Current Model**.
4. Enter calculation assumptions in SI units, then run **Integrated Assurance**.
5. Review hard constraint violations before comparing optimisation options.
6. Enter an author and change note, then use **Run & Commit** to store an immutable, versioned evidence package in the repository.
7. Export coordinated geometry for CAD/BIM coordination. Review an import report before merging external geometry.

## Verified calculation engine

The calculation set currently provides maximum runway wheel load, simply supported runway deflection screening, steady-state hoist design power, and design-life cycle count. Every record stores:

- explicit SI inputs, equations and basis references;
- primary results and an independently coded numerical recheck;
- numerical tolerance and pass/fail result;
- deterministic SHA-256 calculation and evidence hashes;
- limitations and an engineering-approval warning.

A `verified` result confirms repeatability and agreement between the two implemented methods. It does not certify that the selected load cases, factors, material properties or standards are complete for a specific project.

## Constraints-based planning

Hard constraints decide whether a plan is feasible. The engine checks:

- no perpendicular runway crossings at the same height;
- bridge-to-runway and trolley-to-bridge relationship integrity;
- allocated move load against crane SWL;
- resolvable movement endpoints and crane coverage prerequisites;
- route and keep-out constraint definitions.

Soft constraints identify improvement opportunities such as excessive target utilisation. Hard constraints should not be disabled to obtain a preferred result; change the physical design, elevation, allocation or demand instead.

## Advanced optimisation

The optimiser performs deterministic capacity-constrained list scheduling. It evaluates throughput, makespan, active-asset cost, utilisation and resilience using four objective profiles: throughput, balanced, lowest-cost and resilience. Results contain the full move allocation and any infeasibility explanation. The recommended option is a decision-support result and must pass the independent constraint and engineering reviews.

## CAD/BIM interoperability

- **SCX Exchange JSON** is the loss-minimising round-trip format.
- **Geometry CSV** is suitable for schedules, mapping and controlled bulk review.
- **DXF** exports metre-based line geometry on named `SCX_*` layers and preserves SCX IDs.
- **IFC4** exports `IfcBuildingElementProxy` coordination objects and embeds SCX round-trip metadata in a valid STEP comment.

Before merging imported geometry, confirm units, coordinate origin, axis orientation, elevation, layer/type mapping, IDs and relationships. Generic IFC authoring models require an agreed mapping to SCX runway, bridge, trolley and station types.

## Repository artifact types

Committed results appear as `verified-calculation-set`, `constraint-verification-report`, `optimisation-study`, or `integrated-design-assurance`. Each version records author, change note, source model hash, engine version and the full evidence object.

## Engineering limitation

The workbench improves consistency, traceability and early error detection. It does not replace competent engineering judgement, surveyed geometry, manufacturer data, code-compliant structural analysis, safety validation, statutory inspection or independent design approval.