EXPRESS short listing for SMCH
From WikiSTEP
Solid Model Construction History
Abstract Background Scope Model Overview EXPRESS short listing Implementation and Part 21 File
The construction history schema is intended to be used in conjunction with other parts to provide modular capabilities. The initial implementation which is discussed here extends the capability of AP 203.
This section specifies the EXPRESS schema that uses schemas from existing parts or documents. The ‘final’ short form will include USE FROM statements that utilize concepts or definitions from the following documents/publications.
Part 108 (Parametrization and constraints for explicit geometric product models-N526);
Feature-Based Construction Operations (N 589);
Part 42 Ed2 (Geometric and topological representation) ;
Part 108 contains the data structures for general representations for parametrized quantities and for constraint relationships between entity instances in models. Transfer of this information with product shape models of Brep and related types captures key aspect of design intent that govern the behavior of a transmitted model in a receiving system. In this version of the short form the Part 108 schema are commented out since the updated EXPRESS is currently not available. It is expected to be available within the next few weeks, and this schema will be updated accordingly.
Feature-Based Construction Operations structures provides definitions for representations of parametric extrusions, blends, and chamfers. Compatibility with comparable concepts in Part 214 or Part 224 is intended to be maintained, as appropriate.
Part 42 Edition 2 contains some additional structures, especially solid primitives, not included in the IS version (1994).
The latest version of AP 203 being implemented in CAx-IF has the schema name CCD_CLA_GVP_AST_ASD, and is used in the following short form. It was input to SHTOLO to create the long form schema which is available as a companion to this document.
