Downloaded from https://www.everyspec.com APPENDIX C MIL-STD-31000A C.9 EXHIBIT C – DERIVATIVE MODEL VALIDATION CRITERIA Errors occur in derivative models when a source model is translated to a derivative format. If a source model is correct prior to translation and contains intrinsic errors after translation, then a translation error has occurred. However, some errors may be detectible only by comparing the source model with the derivative model. These criteria definitions are proposed based on MBD interoperability process validation studies within the DoD community.
C.9.1 Face geometry validation criteria Each of these face validation criteria apply to faces translated from any topological form – an independent (unsewn) face, a face in an open shell or a face in a solid. C9.1.1 Unmatched Face (G-FA-UM) Definition: A face in one model has no corresponding face in the other model. Measurement: The criterion is false if any face in the native model does not have a corresponding face in the translated model. Effects of condition on model-based definition translation: If the unmatched face is in the native model, it represents significant data loss.
If the unmatched face is in the translated model, it causes confusion and is generally the result of incorrect filtering during the translation process. For example, a hidden face intended for construction reference in the native model has been included in the translated model when only the (visible) product-defining geometry was intended. 137