Downloaded from https://www.everyspec.com APPENDIX C MIL-STD-31000A Data exchange: May cause trimming problems with faces. Finite element analysis: May cause excessively fine mesh element to be generated. Numerically controlled manufacturing: May cause tool path generation to fail. Recommended correction: Remove the redundant knot points if possible. If the CAD software does not permit knot removal, recreate the surface with the proper number of knots. C.7.2.10. Self-intersecting surface (G-SU-IS). Definition: A surface or patch intersects itself at one or more locations. Within the threshold value, the logical value is true if there is no intersection.
Effects of condition on CAD data quality: Design and drafting: Solid models with self-intersecting surfaces may fail unexpectedly. Data exchange: May cause trimming problems with faces, failure of solid models to sew. Finite element analysis: Automatic mesh generation may fail. Numerically controlled manufacturing: Gouging and other unsatisfactory cuts may occur. Recommended correction: Remove the self-intersecting surface and recreate it in a way that does not produce a self-intersection. This process may require replacing self-intersecting curves that define the surface. Trim the self-intersecting portion to the curve of intersection. 97