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ISO 25297-2:2011 NODIF to ISO 23584 Reference Dictionary Mapping for Optical Data
Optics and photonics – Reference dictionary – Part 2: Mapping from NODIF to ISO 23584 dictionary entries
1. Introduction to ISO 25297-2: Mapping NODIF to ISO 23584
ISO 25297-2:2011 specifies the mapping tables and rules for transforming NODIF (ISO 25297-1) optical design data into the ISO 23584 (Optics and photonics – Reference dictionary) structured data format. This standard bridges two important domains: the parametric optical design data captured by NODIF, and the standardized reference dictionary framework defined by ISO 23584 (based on ISO 13584 and IEC 61360).
The mapping enables optical component data to be used within a broader PLM (Product Lifecycle Management) framework, where standardized dictionaries provide semantic interoperability across design, manufacturing, procurement, and maintenance systems. By mapping NODIF entities to ISO 23584 dictionary entries, optical components described in design software can be automatically linked to enterprise resource planning (ERP) systems, supplier databases, and catalog management platforms.
For optical engineers working in large enterprises, this mapping means that optical designs created in specialized software can flow directly into procurement catalogs and supply chain systems without manual data re-entry, dramatically reducing errors and cycle times in the transition from design to manufacturing.
2. The ISO 23584 Reference Dictionary Framework
2.1 ISO 23584 Structure and Principles
ISO 23584 defines a reference dictionary for optics and photonics using the ISO 13584/IEC 61360 methodology. The dictionary is organized as a hierarchical classification system where each class has associated properties, each with well-defined data types, units, and value ranges. The dictionary supports multiple languages and includes explicit definitions, references to international standards, and relationship types between classes.
| Mapping Level | NODIF Entity | ISO 23584 Dictionary Entry | Mapping Complexity |
|---|---|---|---|
| Class | optical_surface | EOT 100001 (Optical surface class) | Direct: 1-to-1 |
| Property | radius_of_curvature | EOT 200001 (Radius of curvature) | Direct: unit conversion |
| Property | aspheric_coefficient_A4 | EOT 200015 (4th order aspheric coeff.) | Direct: naming alignment |
| Class | optical_material | EOT 110001 (Optical material class) | Direct: 1-to-1 |
| Property | refractive_index_nd | EOT 210001 (Refractive index nd) | Direct: unit conversion |
| Constraint | aperture_limits | EOT 300001 (Aperture constraint) | Indirect: needs decomposition |
The ISO 23584 dictionary is identified with the prefix “EOT” (Essentials of Optics and Photonics) and organizes optical concepts into a multi-level taxonomy. Class codes in the 100000 range represent object classes (things), property codes in the 200000 range represent properties, and constraint codes in the 300000 range represent relationships and constraints.
2.2 Mapping Methodology and Rules
The mapping process follows a systematic four-step methodology. First, the NODIF EXPRESS schema is analyzed to identify all entities, attributes, and constraints. Second, corresponding ISO 23584 dictionary entries are identified or, where necessary, new entries are proposed. Third, attribute mapping rules are defined, including unit conversions, naming alignments, and structural transformations. Fourth, validation rules ensure that mapped data maintains consistency with both source and target schemas.
Not all NODIF entities have exact equivalents in the ISO 23584 dictionary. When a direct mapping is not available, the standard provides three strategies: decomposition (splitting a complex entity into simpler components), composition (combining multiple entities into one), or extension (proposing new dictionary entries through the ISO 23584 maintenance process).
3. Engineering Implementation Guidance
3.1 Implementation Architecture
A complete implementation requires three processing stages. Stage 1 is NODIF parsing: read the STEP physical file (ISO 10303-21), extract entities and attributes, and build the NODIF data structure. Stage 2 is dictionary mapping: apply the mapping rules from ISO 25297-2 to transform NODIF entities into ISO 23584 dictionary structures, handling unit conversions (millimeters to meters, degrees to radians, etc.) and structural transformations. Stage 3 is dictionary output: generate the ISO 23584-compliant dictionary file in the required exchange format (typically ISO 10303-21 or the PLIB XML format defined in ISO 13584-24).
The mapping tables in ISO 25297-2 cover approximately 150 entity-to-class mappings and over 400 attribute-to-property mappings. Key mapping complexities include unit conversion (NODIF typically uses millimeters, while ISO 23584 uses meters as the base unit for length), sign convention alignment, and handling of optional attributes that may or may not be present in a given design.
3.2 Validation and Testing
Validation of NODIF-to-ISO-23584 mapping implementations requires testing with a comprehensive set of reference optical designs covering all five NODIF UoFs. The standard recommends using at least 20 test cases spanning simple singlets, cemented doublets, air-spaced triplets, aspheric singlets, diffractive optical elements, and multi-element zoom systems. Each test case checks for completeness (all entities mapped), correctness (numerical values preserved within tolerance), and consistency (relationships maintained).
Best practice: Maintain a bidirectional mapping validation suite. Export a design as NODIF, map to ISO 23584, then attempt to reverse-map back to NODIF. Compare the round-tripped design with the original. Key metrics: surface count should match exactly, radii within 0.001%, thicknesses within 0.01%, and all material designations preserved.
4. Frequently Asked Questions
Q1: What is the primary use case for ISO 25297-2?
The primary use case is integrating optical design data into enterprise PLM (Product Lifecycle Management) systems. By mapping NODIF design data to ISO 23584 dictionary entries, optical components become searchable, comparable, and manageable within the same framework used for mechanical, electrical, and electronic components.
The primary use case is integrating optical design data into enterprise PLM (Product Lifecycle Management) systems. By mapping NODIF design data to ISO 23584 dictionary entries, optical components become searchable, comparable, and manageable within the same framework used for mechanical, electrical, and electronic components.
Q2: Does the mapping support all optical surface types?
Yes, the mapping tables cover spherical, aspheric, diffractive, and freeform surfaces. However, the level of detail preserved depends on the ISO 23584 dictionary entries available. Freeform surfaces, being the most complex, may require decomposition into multiple dictionary entries.
Yes, the mapping tables cover spherical, aspheric, diffractive, and freeform surfaces. However, the level of detail preserved depends on the ISO 23584 dictionary entries available. Freeform surfaces, being the most complex, may require decomposition into multiple dictionary entries.
Q3: How are material properties mapped between NODIF and ISO 23584?
Optical materials are mapped through their ISO 23584 dictionary class entries. Properties such as refractive index, Abbe number, internal transmittance, and dispersion coefficients are mapped individually. The standard defines mappings both for catalog glasses (e.g., Schott, Ohara) and for user-defined materials with measured properties.
Optical materials are mapped through their ISO 23584 dictionary class entries. Properties such as refractive index, Abbe number, internal transmittance, and dispersion coefficients are mapped individually. The standard defines mappings both for catalog glasses (e.g., Schott, Ohara) and for user-defined materials with measured properties.
Q4: What happens when a mapping is ambiguous?
The standard defines a precedence hierarchy: exact match takes highest priority, followed by semantic equivalent (different name but same meaning), then decomposition (splitting into multiple mappings), and finally extension (marking as unmapped with a note). Ambiguous mappings are documented in the mapping report generated by the implementation.
The standard defines a precedence hierarchy: exact match takes highest priority, followed by semantic equivalent (different name but same meaning), then decomposition (splitting into multiple mappings), and finally extension (marking as unmapped with a note). Ambiguous mappings are documented in the mapping report generated by the implementation.
