# Step 3: mitc4-element-model

## Read First

Read these files before editing:

- `/AGENTS.md`
- `/docs/AGENT_RULES.md`
- `/docs/ARCHITECTURE.md`
- `/docs/implementation-plans/analysis-model-objects-implementation-plan.md`
- `/include/fesa/element/Element.hpp`
- `/include/fesa/core/ElementDefinition.hpp`

## Task

Add a MITC4 element model object skeleton.

Allowed files:

- Create `/include/fesa/element/Mitc4Element.hpp`
- Create `/src/element/Mitc4Element.cpp`
- Create `/tests/element/mitc4_element_model_test.cpp`
- Modify `/CMakeLists.txt`

Required behavior:

- `Mitc4Element` derives from `Element`.
- Stores element id, four node ids, and property id.
- Reports `ElementType::Mitc4`.
- Reports `nodeCount() == 4`.
- Reports `dofCount() == 24`.
- Preserves connectivity order.

## Tests To Write First

Write `/tests/element/mitc4_element_model_test.cpp` before production changes:

- Construct `Mitc4Element`.
- Access it through `const Element&`.
- Verify id, type, node count, DOF count, connectivity, and property id.

Run targeted build and confirm RED because `Mitc4Element.hpp` is missing.

## Acceptance Criteria

Run:

```powershell
python scripts/validate_workspace.py
ctest --test-dir build/msvc-debug --output-on-failure -C Debug -R model-object
```

Update step 3 status.

## Do Not

- Do not implement element stiffness, Jacobians, MITC shear interpolation, resultants, stress, or integration-point state.