Downloaded from https://www.everyspec.com APPENDIX C MIL-STD-31000A C.7.1.6. Self-Intersecting curve (G-CU-IS). Definition: A curve intersects itself at one or more locations. Self-intersections are usually caused by errors in creating offset curves. Within threshold value, the logical value is true if there is no intersection. Effects of condition on CAD data quality: Design and drafting: Errors may occur if the curve is used to create swept or lofted surfaces or other offset curves. Solid features may fail unexpectedly. Data exchange: May cause trimming problems with faces. Finite element analysis: Automatic mesh generation may fail. Excessively fine local mesh may be generated.
Numerically controlled manufacturing: Gouging and other unsatisfactory cuts may occur. Recommended correction: Recreate the offset curve in a way that does not produce a self- intersection. Trim the self-intersecting portion of the curve. C.7.1.7. Embedded curves (G-CU-EM). Description: A set of overlapping curves of any type. Embedded curves may be cause by CAD operator error (such as inserting the same curve twice) or by copying geometry from another source into the model. Within precision of 0.01 mm, the logical value is true if there is no embedded curve. Effects of condition on CAD data quality: Design and drafting: Profiles containing embedded curves may cause features to fail.
Errors may occur when selecting curves. Data exchange: May cause trimming problems with faces. 88