Downloaded from https://www.everyspec.com APPENDIX C MIL-STD-31000A Figure 9. Re-mastering of feature-based 3D models A special case of re-mastering may be used when assemblies are converted from one system to another. It is possible to translate individual parts as featureless solids, translate non-graphic attributes of each part, and assemble parts using assembly constraints. This type of re-mastering produces a robust model that can be used to create assembly animations, analytical models, and exploded-view drawings. This type of partial re-mastering is generally easier to automate than fully featured masters. C.6.6. Long-term archiving of 3D model data.
Increasingly designers of military systems are employing 3D models as the masters for manufacturing. Standards such as ASME Y14.41-2003 Digital Product Definition Data Practices are defining conventions for applying critical dimensions and tolerances directly to 3D models. These practices are eliminating the need to generate fully dimensioned 2D drawings to manufacture products. DoD systems are often characterized by long services lives. An extreme example is the M2 Browning .50 Caliber machine gun, which entered service in 1933 and remains in use today.
The need to produce spare parts and additional complete units of weapons systems requires the DoD to have access to engineering documents that precisely define these systems. To assure that future spare parts or production runs are faithful to the original design, the DoD requires standards for acceptance of 3D master models that can serve as long-term engineering records. The technical problem with retrieval of models that have been archived for long periods is that 3D CAD systems are continually evolving. Although CAD systems are supposed to be able to read 82