PDF 3D Formats
PDF 1.7 (ISO 32000-1:2008) introduced interactive 3D support using the U3D file format. PDF 2.0 (ISO 32000-2) expanded 3D support to include the ISO PRC format, STEP (AP242) 3D models, and glTF 2.0. Refer to ISO 32000 for details on correctly embedding 3D data models in PDF files.
ECMAscript (JavaScript) can also be used to manipulate and interact with 3D models in PDF files (refer to ISO 21757 for details).
The PDF Association’s 3D PDF Technical Working Group provides a forum for members to focus on specifications and guidance for implementing 3D PDF technology.
ISO 14739 (PRC)
ISO 14739-1:2014 Document management — 3D use of Product Representation Compact (PRC) format — Part 1: PRC 10001 describes a product representation compact (PRC) file format for three-dimensional (3D) content data. This format is designed to be included in PDF (ISO 32000) and other similar document formats for the purpose of 3D visualization and exchange. It can be used for creating, viewing, and distributing 3D data in document exchange workflows. It is optimized to store, load, and display various kinds of 3D data, especially those from computer-aided design (CAD) systems.
Note that PRC has unresolved issues (GitHub query) and resolved errata. ISO TC 171 SC 2 WG 7 is working on a dated revision of PRC to formally correct these issues.
The registered IANA Media type for PRC is model/prc.
Universal 3D (U3D)
The U3D file format is defined by ECMA-363 and was originally introduced as part of PDF 1.7 (ISO 32000-1:2008).
The registered IANA Media type for U3D is model/u3d.
STEP (AP 242)
ISO/TS 24064 is a PDF 2.0 extension that defines how to use STEP (AP242) with PDF 2.0. STEP is developed and maintained by a different ISO technical committee (ISO TC 184) than the ISO technical committee responsible for PDF (ISO TC 171). Like other ISO standards, STEP is copyrighted by ISO and is not freely available. However, the 10303 EXPRESS schemas are freely available, as are the recommended practices for implementers.
The registered IANA Media types for STEP are model/step, model/step+xml, model/step+zip, and model/step-xml+zip.
glTF 2.0
ISO/TS 32007 is a PDF 2.0 extension that supports The Khronos Group’s glTF 2.0 format in PDF 2.0.
The registered IANA Media types for glTF are model/gltf+json and model/gltf-binary.

Download ECMA-363 (U3D)
Buy ISO 14739 (PRC)
Buy ISO/TS 24064 (STEP)
Buy ISO/TS 32007 (glTF)
PDF 1.7 introduced interactive 3D support using the U3D file format. PDF 2.0 expanded 3D support to include the ISO PRC format. ISO extensions have added support for STEP (AP242) and glTF 3D models in PDF.
Communities: 3D PDF TWG, 3D PDF User LWG
ISO Group Responsible: ISO TC171 SC2 WG7
ISO Status: status of all PDF-related ISO work