1.1 Introduction
This document defines the requirements for the long term digital preservation of the Semantic Representation of Product and Manufacturing Information (PMI) with their possible links to the 3D explicit shape and geometry of single CAD parts. The goal is to preserve this 3D information, without loss, with respect to the geometry produced by the original CAD system, following the principles laid down in EN 9300 003 “Fundamentals and Concepts”.
The requirements of EN 9300 110 concerning the preservation of the 3D explicit shape shall apply within this Part.
The term “semantic representation” is defined in Clause 3 “Terms, definitions and abbreviations”.

1.2 In scope
The following outlines the total scope of EN 9300 121:
- machine-interpretable PMI “Semantic Representation” (Refer to clause 3 for definition);
- the association of the above with 3D geometric shapes;
- the possible association of the above with Presentation of 3D Product and Manufacturing Information (PMI), and 3D annotations as defined in EN 9300 120.
In EN 9300 121, the technology used to preserve this 3D information is based on semantic representation. The main use cases are Certification, Product Liability and Design re-use.
For the purpose of this document, the semantic definition is at the level that supports associative “Cross-highlighting” for the purpose of human readability.

1.3 Out of scope
The following is outside the scope:
- PMI presentation (defined in EN 9300 120);
- User defined attributes that are assigned to 3D geometric entities or at the part level. The archiving of the UDA is defined in EN 9300 120.
- How to preserve additional information:
- - property rights;
- - form features;
- - CAD Assemblies.
- The semantics of special Notes outside the scope of PMI: ITAR/EAR, proprietary, and title block information, etc.