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How to convert PRC (Adobe 3D PDF) to OBJ (Wavefront .obj,.mtl)?

PolyTrans|CAD+DCC performs mathematically precise CAD, DCC/Animation, GIS and BIM 3D file conversions into all key downstream 3D packages and file formats. Okino software is used and trusted throughout the world by many tens of thousands of 3D professionals in mission & production critical environments, backed by respectable personal support directly from our core development team.

PRC

PRC (Product Representation Compact) is probably one of the least known of 3D CAD file formats yet it forms the underpinning for Adobe Acrobat 3D PDF files. It may be considered the “silent younger brother of the more well known U3D file format”. It has a fairly long but little unknown history.

PRC is primarily used as a 3D file format to embed 3D data within a PDF file. It was originally developed by the TTF Group of France whom were purchased by Adobe in 2006. In 2014 PRC became an ISO published standard.

Okino's PRC geometry import converter reads in native PRC 3D CAD files. It will also extract PRC and U3D files from within any chosen page of an Adobe 3D PDF file. It is an intelligent and well implemented importer for all forms of complex source PRC CAD file data, including the import and processing of 3D mesh and BREP (solids) geometry, assembly hierarchy (incl. intelligent “proto node” handling), materials (with adherence to the PRC father/son inheritance rules), 2D bitmapped texture maps and meta data.

OBJ

Wavefront OBJ is a little understood but highly used and prevalent 3D "polygonal mesh" file format used throughout the 3D graphics world. Okino, Alias Research and McNeel made it popular in the early to mid 1990s as a general purpose, simple-to-read, storage and transmission 3D file format, especially for the then-new companies who began to sell 3D mesh models via the Internet.

Relatively speaking, OBJ is a rather simple file format but a bit better than STL although similar to the more modern 3MF format.The OBJ format allows for 1 or more unique polygonal mesh objects to be defined, each with optional UV texture coordinates and vertex colors. Material definitions can be linked to the mesh geometry as defined in the separate 'MTL' file. The material definitions are rather simple (ie. no PBR material support) but acceptable, and with varied levels of texture mapping support. OBJ format does not provide support for object hierarchy, local transformations, meta data, lights, cameras, skinning or animation. Most notably, OBJ does not allow for 'object instancing' and hence 1000 copies of a screw would be saved to OBJ as 1000 explicit copies, rather than 1000 references to one master object.

A short history: In the 1980s there was a program called Wavefront Visualizer which ran on UNIX and ran its early rendering pipeline as a series of tee'd command line 'applets'. The data flowed from one applet to another via various ASCII based files - OBJ for geometry, MTL for materials and other ASCII files for animation, skinning, deformation, etc.

Okino knows of the Wavefront OBJ file very well as it provides the one and only full implementation of the OBJ file format and with the ability to consume exceedingly large OBJ files quickly and efficiently. This includes the only known implementation of OBJ-centric 'NURBS geometry' (surfaces and curves) within the OBJ file format (which is little or not used) other than that from the McNeel Rhino-3D software.

PRC import converter's overview

OBJ export converter's overview