Specification of a CAD * I Neutral File for CAD Geometry

to the Specification.- 1.1 Purpose.- 1.2 The relation between this proposal and STEP.- 1.3 Stucture of the document.- Approach.- Basic principles.- 3.1 Use of formal languages.- 3.2 Informal description of the CAD data schema.- 3.3 The physical level.- 3.4 Validation of the CAD model transfer.- Reference Manual.- The high level data specification language HDSL.- 4.1 Type declaration.- 4.2 Predefined types.- 4.3 Composite types.- 4.4 The types Reference,Ref_Only.- 4.5 Generic types.- 4.6 The predefined function Dimension.- 4.7 Rules applying to building a schema with HDSL.- 4.8 Semantics of reference models defined with HDSL.- The CAD*I reference model specification.- 5.1 Attribute types for general use.- 5.2 General data base structure.- 5.3 Referencing mechanisms.- 5.4 Geometric model entities.- 5.5 Points and Curves.- 5.6 Surfaces.- 5.7 Geometry on surfaces.- 5.8 Boundary representations.- 5.9 Constructive solid geometry.- 5.10 Hybrid_Solid.- 5.11 General grouping mechanism.- 5.12 Placement and instancing.- 5.13 Test data elements.- 5.14 Miscellaneous.- 5.15 Parametric modeling.- 5.16 Extensions of the reference mocel under consideration.- Levels of schema implementations.- 6.1 The geometric modeling levels.- 6.2 The assembly structure.- 6.3 Parametric models and macros.- 6.4 References.- The physical layer.- 7.1 The physical level.- 7.2 The metafile level.- 7.3 The alphabet level.- 7.4 Tokens of the neutral file language.- 7.5 The statement level.- 7.6 Rules for translating from the HDSL into BNF.- 7.7 Structure of the neutral file language.- Implementation Guidelines.- Definition of the state machine post-processor.- 8.1 The finite state approach.- 8.2 Interpreter.- 8.3 World.- 8.4 Entity with scope (expect World).- 8.5 Begin scope definition.- 8.6 End scope definition.- 8.7 Close entity.- 8.8 Entity world.- 8.9 Property definition.- 8.10 Interpertation of argument lists (expect references).- 8.11 References.- 8.12 Examples of error messages.- State lists.- Relationships between operating systems and CAD.- 10.2 Data bases and libraries.- Programming rules for CAD*I processors.- 11.1 Programming language.- 11.2 Software design.- Programming interface.- 12.1 Mapping of HDSL data types onto Fortran.- 12.2 Application program interface routines.- Comments on pre-processors.- 13.1.1 Implementation of level 1 and level 2 per-processor routines.- Comments on post-processors.- The interface of the CAD*I parser.- 15.1 Parse tree.- 15.2 Example.- Appendix A. The graphical alphabet.- Appendix B. The escape sequences.- B.1 The Latin alphabet (ISO6937).- B.2 The Greek alphabet.- B.3 The Kanji alphabet.- Appendix C. Alphabet translation into a private alphabet.- Appendix D. A neutral file for fixed format letters.- Appendix E. Examples of a CAD*I neutral files.