This document specifies how to extend the ISO 32000-2 specification by adding the ISO 10303-242 (STEP AP 242) format as a valid format for 3D assets contained in a RichMedia annotation. It is intended for: —     developers of software that creates PDF files (PDF writers); —     software that reads existing PDF files and usually interprets their contents for display (PDF readers); —     software that reads and displays PDF content and interacts with the computer users to possibly modify and save the PDF file (PDF processors); —     PDF products that read and/or write PDF files for a variety of other purposes (PDF processors). Note             PDF writers and PDF readers are more specialised classifications of PDF processors. This document does not specify the following: —     specific processes for converting paper or electronic documents to the PDF file format; —     specific technical design, user interface implementation, or operational details of rendering; —     specific physical methods of storing these documents such as media and storage conditions; —     methods for validating the conformance of PDF files or PDF processors; —     required computer hardware and/or operating system.