What is ASME Y14.5 — GD&T?
ASME Y14.5 is the American standard for Geometric Dimensioning & Tolerancing (GD&T). It defines a system of symbols and rules to express form, orientation, position, and runout tolerances on technical drawings. GD&T is the alternative to classical ± tolerances for complex geometric characteristics. Its ISO equivalent is the ISO GPS series.
The 14 GD&T characteristics
- Form: straightness, flatness, circularity, cylindricity
- Profile: profile of a line, profile of a surface
- Orientation: parallelism, perpendicularity, angularity
- Position: position, concentricity/coaxiality, symmetry
- Runout: circular runout, total runout
How to balloon a GD&T tolerance?
Each feature control frame (symbol + tolerance value + datum references) is a separate characteristic that must receive its own balloon. Examples in Form 3:
- Balloon 12 — Perpendicularity ⊕ ⌀0.05 A — Nominal: 0 — Tolerance: ⌀0.05
- Balloon 13 — Position ⌀0.1 A B C — Nominal: 0 — Tolerance: ⌀0.1
- Balloon 14 — Flatness 0.02 — Nominal: 0 — Tolerance: 0.02
BullePlan and GD&T: AI extraction
BullePlan detects and extracts GD&T feature control frames during AI analysis. Each frame is treated as a distinct characteristic with its symbol, tolerance value, and datum references. The generated Form 3 automatically includes these characteristics with the full GD&T frame description — for both ASME Y14.5 and ISO GPS drawings.