What problem does it solve? Turning natural-language specs, reference images, or technical drawings into correct parametric CAD geometry is slow and error-prone, and generated STEP files often ship with silent geometry defects. This Skill provides a complete workflow for authoring build123d model scripts, building deterministic STEP/STL/3MF/GLB outputs, and validating them with geometric inspection and mandatory snapshot review. ## Core Features & Use Cases - Parametric model authoring: Write plain Python model scripts with decorated functions that build closed, labeled solids and assemblies, with parallel builds, freshness tracking, and a content-addressed store. - Geometry inspection and validation: Run refs, measure, align, frame, diff, validate, and interference checks against STEP documents, using selector refs like #o1.2.f1 or part labels. - Snapshot review and mesh export: Render PNG review packets of STEP or mesh files, declare STL/3MF/GLB outputs, and attach kinematics mates or animation clips for viewer posing. - Use Case: Ask for a two-piece 120 x 80 x 35 mm enclosure with aligned screw bosses; the Skill writes the model scripts, builds the STEP assembly, validates boss alignment and bounding box, snapshots the result, and hands the file to the CAD viewer. ## Quick Start Ask the agent to create a parametric CAD part from your dimensions, for example a mounting plate with four M4 clearance holes, and have it build, validate, and snapshot the STEP output.
