AIA/NAS NAS9300-115

Abstract

NAS9300-115 describes the requirements, and particularly the information required, for the long term archiving and retrieval of a mechanical CAD explicit assembly structure. This will allow the retrieval of the assembly structure including the placement information. <br>The CAD assembly structure defines the collection of CAD parts into assemblies, and assemblies into higher level assemblies. An assembly can contain several occurrences of the same part or subassembly. <br>The assembly structure is a tree, in which the leaf nodes are individual parts, and the non-leaf nodes are assemblies. The parent/child relationship between two nodes records not only that the child is part of a higher assembly, but also the relative position of that child in that assembly. <br>This standard covers the archiving of the tree structure and the associated positioning information. The geometry of the individual component parts is out of scope. <br>The assembly structure can be recorded in the same file as the geometry, or can cite the geometry as an external reference. <br>The assembly structure can be supplied as a single file, or as a set of files, with cross references between files. <br>Note: An assembly node may contain geometry that is defined directly in the coordinate system of the assembly rather than through a child node with a corresponding transformation matrix to move the part into the assembly co-ordinate system. Some modeling systems call this a hybrid assembly. This kind of assembly is within the general scope of this part; however no specific verification and validation rules for this geometry are defined. <br><strong>Out of scope:</strong> </span><ul> <li>&#61623; The archiving of the geometric model of the components;</li> <li>&#61623; The management of different occurrences of the same part that have different geometry.</li> <li>&#61623; The management of different occurrences of the same part that have different attributes.</li> <li>&#61623; The archiving of assembly-by-constraint (where, for example, the position of a part is given as "perpendicular to part X", rather than given as a positioning matrix);</li> <li>&#61623; The archiving of the Geometrical Dimensioning and Tolerance (GD&T);</li> <li>&#61623; The archiving of assembly Form Features.</li></ul> <br>Note: Product assembly structure may be defined based on the data base management system approach. This case uses other fundamental concepts not covered in this part. Ref. family NAS 9300 2xx.<br>