feat(skills): GD&T and drawing best-practice skill #182

Goal

An agent skill that teaches the model GD&T and drawing best practice, so the drawings it makes through this server are ones a machinist can work from, not just ones with dimensions on them.

This is a placeholder: the scope below is a starting point to refine before it is specced.

Why

The drawing tools can now import model dimensions, add centre marks, notes, a title block and a BOM. What they can't do is decide which dimensions a part needs, where the datums are, or what tolerance a hole needs. The model has to know that, and today nothing tells it. Working on the README demo (a drilled mounting plate) showed the gap: the tools placed every dimension they were given, but choosing a dimensioning scheme was left to the prompt.

What the skill could cover

• Datums. Picking a datum reference frame (A/B/C) from how the part is located and mounted, and dimensioning from it.
• Dimensioning practice. Fully defining a part without double dimensioning; baseline versus chain dimensions; hole patterns as 4X Ø5.5 THRU with basic locations; which view each dimension belongs in.
• Tolerances. Sensible defaults by process (machined, laser cut, 3D printed), a general-tolerance note, and when a feature needs its own tolerance.
• Feature control frames. When to use position, flatness, perpendicularity or profile, and how to write them (ASME Y14.5 and ISO 1101, with the differences noted).
• Checking. Reading a drawing back (the existing analysis and verify_model tools) and flagging an under-dimensioned or over-dimensioned part.

Open questions

• Which standard by default: ASME Y14.5 or ISO GPS? Probably configurable, ISO for the A3 ISO sheet format the generator uses.
• Does adding feature control frames and datum symbols need new tools (SolidWorks InsertGtol, InsertDatumTag2), or can the first version be guidance only?
• Ship it in the same skill as feat(skills): ship an agent skill for using the server #175 or as its own?

Related

• feat(skills): ship an agent skill for using the server #175: ship an agent skill for using the server
• docs(readme): end-to-end demo GIF - prompt to SolidWorks part to reproduction script #147: bracket demo, ending in a drawing package