Drawing Diff Analyzer

Problem

During design review, 2D engineering drawings and 3D models often disagree on dimensions, outlines, or tolerances, and manual line-by-line checks are slow and error-prone. Drawing Diff Analyzer targets this workflow: it accepts DWG/DXF/PDF drawings plus STL/STEP/IGES models, extracts comparable geometry, and produces a structured diff report so engineers can quickly spot nonconforming or unverified items.

How It Works

• 2D drawing parsing: uses dependencies such as ezdxf, pdfplumber, and fitz to extract outlines, circles, arcs, linear/angular dimensions, and annotations like Ø10, R10, or 10±0.05; it also recognizes geometric tolerances such as position, perpendicularity, and flatness.
• 3D model parsing: uses numpy-stl, trimesh, or cadquery to extract vertices, edges, faces, and bounding-box dimensions into a comparable feature set.
• Diff comparison and reporting: compares dimension deviation, outline deviation, and geometric tolerance notes; supports --tolerance for the tolerance threshold, defaulting to 0.1mm; outputs diff_report.json and diff_report.md for traceability and review discussion.

Boundaries

The skill defaults to orthographic projection when comparing 3D-derived outlines to 2D geometry, and results depend on drawing quality and coordinate-system integrity. Geometric tolerances are typically recorded and flagged rather than automatically verified from the 3D model alone, so final confirmation still requires manual measurement.