Specification of a CAD*I Neutral File for Solids

Edited for Working Group 2 (WG 2): Cisigraph, Cranfield Institute of Technology, Danmarks Tekniske Hojskole, Kernforschungszentrum Karlsruhe GmbH, NEH Consulting Engineers ApS, Universität Karlsruhe

Contenu

1.0 Purpose.- 2.0 Approach.- 2.1 CAD modelling and data storage.- 2.2 Steps taken in the development of the file specification.- 2.3 The finite State machine approach.- 3.0 Basic Principles.- 3.1 Relationships between operating systems and CAD.- 3.2 Informal description of the CAD data schema.- 3.2.1 Entities, attributes, references.- 3.2.2 Relations, properties.- 3.2.3 Scopes.- 3.2.4 External references.- 3.2.5 Worlds and libraries.- 3.2.6 Assemblies and components.- 3.2.7 Geometry, Wireframe, Surface, and Solids.- 3.2.8 Boundary representation.- 3.2.9 Constructive solid geometry.- 3.2.10 Instancing and placement.- 3.2.11 Parametric models.- 3.2.12 Macro facility.- 3.2.13 Material property.- 3.2.14 User-defined name.- 3.2.15 User records.- 3.3 Basic concepts for the physical layer.- 3.3.1 The envelope concept.- 3.3.2 Formal translation from the schema specification.- 3.3.3 Block structure.- 3.3.4 Strictly sequential file.- 4.0 Schema Specification.- 4.1 The high level data specification language HDSL.- 4.2 The formal CAD?I-WG2 schema.- 4.3 Informal description of the schema semantics.- 4.3.1 Any.- 4.3.2 Assembly.- 4.3.3 Boolean.- 4.3.4 Bool_Operand.- 4.3.5 Bool_Operator.- 4.3.6 Bounded_Curve.- 4.3.7 Box.- 4.3.8 B_REP.- 4.3.9 Circle.- 4.3.10 Component.- 4.3.11 Compound_B_REP.- 4.3.12 Construct.- 4.3.13 Curve.- 4.3.14 Cylinder.- 4.3.15 DIM.- 4.3.16 Direction.- 4.3.17 Edge.- 4.3.18 Face.- 4.3.19 Formal_Parameter.- 4.3.20 Geometric.- 4.3.21 Hybrid_Solid.- 4.3.22 Index_Entry.- 4.3.23 Instance.- 4.3.24 Integer.- 4.3.25 Line.- 4.3.26 Linear_Sweep.- 4.3.27 Loop.- 4.3.28 Macro.- 4.3.29 Material.- 4.3.30 Part_Library.- 4.3.31 Placement.- 4.3.32 Planar_Halfspace.- 4.3.33 Plane.- 4.3.34 Point.- 4.3.35 Point_Constant.- 4.3.36 Point_Variable.- 4.3.37 Poly_Face.- 4.3.38 Poly_Hedron.- 4.3.39 Poll_Loop.- 4.3.40 Predefined.- 4.3.41 Primitive.- 4.3.42 Real.- 4.3.43 Record.- 4.3.44 Record_Type.- 4.3.45 Ref_Any.- 4.3.46 Ref_External.- 4.3.47 Ref_Part_Library.- 4.3.48 Region.- 4.3.49 Regulal_Prism.- 4.3.50 Rotation.- 4.3.51 Rotational_Sweep.- 4.3.52 Rot_Axis.- 4.3.53 Rot_Global.- 4.3.54 Rot_Matrix.- 4.3.55 Routine.- 4.3.56 Routine_Library.- 4.3.57 Shell.- 4.3.58 Solid.- 4.3.59 Solid_Cylinder.- 4.3.60 Solid_Sphere.- 4.3.61 Solid_Torus.- 4.3.62 Surface.- 4.3.63 Truncated_Cone.- 4.3.64 Truncated_Pyramid.- 4.3.65 Type_ID.- 4.3.66 Unbounded_Curve.- 4.3.67 Update.- 4.3.68 Vector.- 4.3.69 Vertex.- 4.3.70 World.- 4.4 Levels of schema implementations.- 4.4.1 The geometric modelling levels.- 4.4.1.1 Two-dimensional wire-frames.- 4.4.1.2 Three-dimensional wire-frames.- 4.4.1.3 Surface models.- 4.4.1.4 Single modelling type solids.- 4.4.1.5 Hybrid models.- 4.4.1.6 Full geometric capabilities.- 4.4.2 The assembly structure.- 4.4.2.1 No assembly structure.- 4.4.2.2 Three-level assembly structure.- 4.4.2.3 Full assembly structure.- 4.4.3 Parametric models and macros.- 4.4.3.1 No parametic models, no macros.- 4.4.3.2 Only one parametric capability.- 4.4.3.3 Full parametric capabilities.- 4.4.4 References.- 4.4.4.1 No external references, no library references.- 4.4.4.2 No external references.- 4.4.4.3 No library references.- 4.4.4.4 Full referencing capabilities.- 5.0 The Physical Layer.- 5.1.1 The physical level.- 5.1.1.1 Tape characteristics.- 5.1.1.2 File transfer via Computer networks.- 5.1.2 The metafile level.- 5.1.3 The alphabet level.- 5.1.4 Tokens of the neutral file language.- 5.1.5 The Statement level.- 5.1.5.1 Basic statement productions.- 5.1.5.2 Compression of statements and named attributes.- 5.1.6 Rules for translating from the HDSL into BNF.- 5.1.7 Structure of the neutral file language.- 5.1.8 Arithmetic expressions.- 6.0 Definition of the Neutral File Semantics.- 6.1.1 Interpreter.- 6.1.1.1 Begin Interpretation of the neutral file.- 6.1.2 World.- 6.1.2.1 Open world.- 6.1.2.2 Close world.- 6.1.3 Entity with scope (except World).- 6.1.3.1 Open entity.- 6.1.3.2 Begin scope definition.- 6.1.3.3 End scope definition.- 6.1.3.4 Close entity.- 6.1.4 Entity without scope.- 6.1.5 Property or relation definition.- 6.1.6 Interpretation of argument lists (except references).- 6.1.7 References.- 6.2 Examples of error messages.- 7.0 State Lists.- 8.0 Fortran Binding.- 8.1 General approach.- 8.2 Mapping of HDSL data types onto FORTRAN.- 8.3 Subroutines for interrogating a data base.- 8.3.1 Subroutines for navigating in a data base.- 8.3.2 Subroutines for reading a specific entity from the data base.- 8.4 Subroutines for writing entities into a data base.- 8.5 Subroutines for writing entities onto the neutral file.- 8.6 Subroutines for interrogating a neutral file.- 8.6.1 Subroutines for interrogating the next entity on the neutral file.- 8.6.2 Subroutines for reading the next entity.- 9.0 Comments on Pre-Processors.- 10.0 Comments On Post-Processors.- 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. A Neutral File for Fixed Format Letters.- Appendix D. How this Paper Developed.- D.5 ISO/TC184/SC4/WG1 meeting December 1985.- D.7 Special meeting on processor development.- D.8 Common workshop of WG1, WG2, and WG3.- D.9 Common workshop of WG2, WG6, and WG7.- D.10 ISO/TC184/SC4/WG1 meeting March 1986.