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Home > Supported File Formats > OBJ to COLLADA


How to convert OBJ (Wavefront .obj,.mtl) to COLLADA (.dae)?


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.

     

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.

     

COLLADA

COLLADA (DAE) is a XML-based readable file format of the 2007/2008 era which had an original goal of allowing efficient cross conversion of 3D asset data between all of the major 3D DCC/Animation systems of that era. Many 3D software programs came to implement COLLADA but with varying levels of comformity and data reliability. COLLADA is more generally known as a polygonal mesh file format and not a MCAD/CAD/AEC/GIS format. Today people would usually use FBX over COLLADA, depending on the quality of the associated (and dated?) import/export converters.

Okino created one of the key implementations of the COLLADA file format in its import and export converters. However, it saw little need for them except for exporting into Cinema-4D from 2008 to 2012, as the primary gateway into Google Earth, and as our still-preferred method to move 3D assets into Blender (rather than FBX). COLLADA does have its place in these current and prior times.

Okino has a unique take on the COLLADA file format as Okino was at the very center of the DCC/Animation conversion world. In 2007 Rémi Arnaud and Mark Barnes argued that yet-another 3D file format was required and hence Sony funded their efforts to define COLLADA for the cross conversion of assets between (initially) 3ds Max and Maya. However, what they conveniently ignored was that Okino already had the defacto cross conversion system in place, for the prior decade, based on its BDF (binary data translation file format) for 3ds Max, Maya, Cinema-4D, Softimage, LightWave and others. In the mid 2000's there was a "not invented here" mindset and hence everyone wanted to stamp/force their own 3D file format on the industry: FBX (Autodesk), COLLADA (Sony), 3dxml (Dassault Systems), XAML-3D (Microsoft), U3D (Adobe and Intel), etc. There was little need or reason to have "yet-another" set of new 3D file formats. All, except FBX, would basically come and go as of 2007/2008. The implosion of the DCC/Animation industry of 2005-2007 and the 2008/2009 recession further hampered the long term adoption or need for COLLADA over Autodesk's FBX.

COLLADA is/was a very fine file format but it was really not needed at the time of its introduction in 2007. It only introduced yet-more confusion to the 3D graphics market as to which 3D file format to use to transfer 3D assets between packages. Developers generally implemented v1.4 of the COLLADA file specification then lost interest thereafter.

However, as a saving grace for COLLADA, all of the 3D software packages which had implemented a good COLLADA exporter became instant gateways to move their 3D assets into the then-new glTF file format of the mid 2010s, until such time that these same packages could add in their own glTF exporters.