Machinery's Handbook, 31st Edition
636 Digital Product Definitions Both standards define how current GD&T concepts are applied to digital models. Both standards also explain where rules have changed to account for differing requirements between 2D-based annotation and 3D annotations. Digital Product Definition Data Practices Terms.— The following terms are defined in both ANSI/ASME Y14.41 and ISO 16792. In ISO 16792, rules are modified to recognize ISO drawing practices where those practices differ from predominately US practice as illustrated in ANSI/ASME Y14.41-2012. Rules in both standards cover not only data sets with models only, but also those data sets with models and drawings. See the respective standards for complete rules and definitions. Annotation: Dimensions, tolerances, notes, text, or symbols visible without any manual or external manipulation. Attribute: A dimension, tolerance, note, text, or symbol required to complete the product definition or feature of the product that is not visible but available upon interrogating the model. Design Model: The portion of the data set that contains model and supplemental geometry. Geometric Element: A graphic entity used in a data set. For example: point, line, plane, surface, solid, model coordinate system or crosshatching. Management Data: The data required for the release, control, and storage of product definition data as well as other relevant engineering data. Model: A combination of design model, annotation and attributes that describes a prod uct, seeFig. 16.
MODEL
Annotation
Attributes
Design Model
Model Geometry
Supplemental Geometry
Geometric Elements
Fig. 16. Content of a Digital Model (ANSI/ASME Y14.41-2012) Model Value: The numerical value derived by interrogating the model that quantifies the form and spatial relationships of the geometry composing a design model or assembly of models to the precision (number of decimal places) of the computer system. Model Geometry: Geometric elements in product definition data which represent a designed product. Product Definition Data: Data elements required to completely define a product. Product Definition Data Set: A collection of one or more computer files that discloses (directly or by reference), by means of graphic or textual presentations, or combinations of both, the physical and functional requirements of an item, see Fig. 17. Query: A means of interrogating a digital element or the relationship between digital elements, see Fig. 17.
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