Downloaded from https://www.everyspec.com APPENDIX C MIL-STD-31000A procedures described herein are necessary for producing quality models but are not comprehensive. Additional criteria are desirable for certification of 3D annotations, piping and tubing, wiring and wire harnesses, sheet metal, fiber-reinforced composites, assembly constraints and bills of material, and non-geometric product attributes. As commercially accepted methods are developed for validating these model characteristics, the guide can be extended to include them. C.2 SCOPE.
This guide is intended to act as a reference document for establishing practices for validating the quality of 3D CAD models submitted to or produced by Department of Defense agencies that procure weapons systems, machinery, and equipment. The recommendations contained herein may be applied to 3D models in the proprietary native formats of various CAD/CAM and CAE applications or to equivalent derivative forms of models that have been translated to one of the following: International standard formats such as ISO 10303 Compact visualization formats such as JT Open, ProductView, eDrawings, or 3D PDF Other proprietary commercial CAD native formats.
Complete 3D product models are complex structures. Consequently, there are several aspects of model data that should be checked prior to release for manufacturing or long-term archival storage. At present, software for checking all classifications of model data quality is not available commercially. Consequently, this guide has been designed to be extensible so that additional checks and acceptance criteria can be added to future releases. The following table shows planned quality classifications addressed by this guide in the current and future releases and is subject to change. Geometry consists of the mathematical description of individual part surfaces.
Modern CAD systems employ what is called the boundary representation method for describing model geometry. Boundary representations consist of curves, surfaces, edges, and faces. In a valid model, the faces meet at the edges to form a closed volume.
53 3D model quality classifications Native Derivative Use Case Design & analysis Manufacturing ISO 10303 (STEP) Visualization Translation Geometry release 1 release 1 release 1&2 release 2 release 1&2 Annotations release 1&2 release 1&2 release 1&2 release 1&2 release 1&2 Structure release 3 release 3 release 3 release 3 release 3 Attributes release 4 release 4 release 4 release 4 release 4 Lifecycle data not applicable not applicable release 5 not applicable release 5