Downloaded from https://www.everyspec.com APPENDIX C MIL-STD-31000A C.8 EXHIBIT B – RECOMMENDED NUMERICAL THRESHOLDS FOR GEOMETRY VALIDATION CRITERIA. 134 Automotive industry threshold values Native Derivative Criteria/Use Case Design Analysis Manufacturing ISO 10303 (STEP) Visualization Translation Curve criteria Large curve or segment gap (G-CU-LG) .01 mm max .01 mm max .01 mm max .01 mm max NR .01 mm max Non-tangent curves or segments (G-CU-NT) 2° max O O 3° max O O Tiny Curve or segment (G-CU-TI) .01 mm min. .01 mm min. .005 mm min. .005 mm min. NR .005 mm min.
Self-Intersecting curve (G-CU-IS) 0.01 mm 0.01 mm 0.01 mm .01 mm NR 0.01 mm Surface criteria Non-Tangent surfaces or patches (G-SU-NT) 2° max O O 3° max NR 3° max Narrow surface or patch (G-SU-NA) .01 mm min. A .005 mm min. .005 mm min. NR .005 mm min. Self-intersecting surface (G-SU-IS) .01 mm 0.01 mm .01 mm .01 mm NR .01 mm Edge loop criteria Self-intersecting loop (G-LO-IS) .01 mm 0.01 mm 0.01 mm .01 mm NR .01 mm Face criteria Large edge face gap (G-FA-EG) .01 mm max .01 mm max .01 mm max .01 mm max NR .01 mm max Narrow face (G-FA-NA) .01 mm min. .01 mm min. .01 mm min. .01 mm min. NR .01 mm min. Embedded faces (G-FA-EM) NA A .01 mm min. .01 mm min. NR .01 mm min.
Inconsistent face on surface (G-FA-IT) T T T T T T Shell criteria Large face gap (G-SH-LG) .01 mm max .01 mm max .01 mm max .01 mm max NR .01 mm max Over-used edge (G-SH-NM) >2 A >2 >2 >2 >2 Aerospace Industries Association LOTAR Par 110 recommendations Native Equivalents Criteria Design Analysis Manufacturing ISO 10303 (STEP) Visualization Translation Curve criteria Threshold values Large curve or segment gap (G-CU-LG) .01 mm max .01 mm max .001 mm max .001 mm max NR .01 mm max Non-tangent curves or segments (G-CU-NT) O-0.5° max A O 75° max NR A Surface criteria Fragmented surface (G-SU-FG) A or N ≤ 25 A or N ≤ 25 A or N ≤ 25 2500 patch max.
A or N ≤ 25 A or N ≤ 25 Tiny surface or patch (G-SU-TI) 0.01 mm2 min. 0.01 mm2 min. 0.01 mm2 min. 0.01 mm2 min. NR 0.01 mm2 min. Edge loop criteria Large edge gap (G-LO-LG) .01 mm max .01 mm max .01 mm max 1.0 mm max NR .01 mm max Face criteria Large edge face gap (G-FA-EG) .01 mm max .01 mm max .01 mm max 1.0 mm max NR .01 mm max Large vertex gap (G-FA-VF) .01 mm max .01 mm max .01 mm max 1.0 mm max NR .01 mm max Tiny face (G-FA-TI) 0.01 mm2 min. 0.01 mm2 min. 0.01 mm2 min. 0.01 mm2 min. NR 0.01 mm2 min.
Shell criteria Large face gap (G-SH-LG) .01 mm max .01 mm max .01 mm max 1.0 mm max NR .01 mm max Free edge (G-SH-FR) T U T T T T Over-used edge (G-SH-NM) >2 NR >2 >2 >2 >2 Solid body criteria Embedded solids (G-SO-EM) T T T T T T Legend Code Value agreed by sender and receiver A Optional when required by design O User preference U Not required NR Logical value true T