freecad

# FreeCAD ## From brief to useful part Establish what the part must fit, how it attaches, which dimensions are measured, the units and the intended process/material. Explain a needed measurement in everyday terms. A sketch or photo can guide shape, but does not establish scale or hidden dimensions. Record assumptions separately from requirements. For load-bearing, electrical, medical or other consequential uses, identify the necessary professional/physical validation; do not certify suitability from a CAD preview. Create `design.json` with the brief, named parts/reference envelopes and measurable checks. Read [the design contract](references/design-contract.md) when creating or changing this file. Cover the requirements that matter to the user's job: outside dimensions alone do not establish fit. Use reference shapes for boards, connectors, movement or fastener/tool access, and check those references' dimensions/positions so an accidentally moved or undersized keep-out cannot pass. Build the appropriate model, not automatically an enclosure. `part.FCMacro` is Python executed by FreeCADCmd, not system Python. Use `FreeCAD as App`, `Part`, named inputs and reusable construction functions. Import an existing STEP as a reference when useful; include only user-approved input files in the explicit `sourceFiles` list. Never bundle an entire workspace or hidden credentials. The macro reads inputs from `HARNESS_WORKSPACE`, creates the named document objects and saves `part.FCStd`...