Home > Supported File Formats > IGES to OBJ

How to convert IGES (.igs) 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.

IGES

IGES was the defacto 'go-to' MCAD translation file format but has long since been overtaken by the STEP file format. IGES and STEP are equally good file formats to translate CAD and MCAD model data files but it all depends on how well the files are exported from the corresponding MCAD modeller software.

As an ANSI standard since 1980, IGES has been used in the automotive, aerospace, and shipbuilding industries. Version 5.3 (1996) is the last published and stable standard of IGES. IGES is one of the original CAD vendor-neutral 3D data translation file formats which was designed for high fidelity data exchange between all major professional 3D modelling applications. IGES uses the .igs and .iges file extensions.

Okino's PolyTrans|CAD provides for a defacto 3D IGES file conversion solution used by the world's primary & professional engineering, aerospace, military, corporate, animation/multi-media and VR/AR industries.

A much deeper overview plus explanation of IGES, and how it can be best used + understood, is outlined in this Okino WEB page. It is vitally important to understand the differences between "old school" and "new school" IGES files, as this is little understood by most 3D graphics users.

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.

More information about IGES

IGES import converter's overview

OBJ export converter's overview