Downloaded from https://www.everyspec.com APPENDIX C MIL-STD-31000A Geometry is used in a variety of manufacturing processes including numerically controlled milling, turning, and cutting; making of jigs, fixtures, and hard gauges; additive fabrication; and coordinate- measuring-machine (CMM) inspection. Model geometry also is used along with attribute data in various analytical processes including finite-element analysis, computational fluid dynamics, kinematics, and dynamics. Figure 1.
Example of 3D model geometry Annotations are attached to 3D geometry to provide additional manufacturing information such as important dimensions and tolerances, datum features, notes, flags, and symbols for properties such as surface finish or weld types. Figure 2. 3D model geometry with annotations Model Structure refers to the relationships among parts in a product assembly and among features in a feature-based part. The structure of most complex product models is hierarchical. Complex assemblies consist of subassemblies containing parts or possibly more subassemblies. Parts of feature-based CAD models consist of a base feature onto which additional features are applied.
Features may themselves have dependent features. 54