3D Design Magazine's "In The Lab", features Okino's PolyTrans 3D data translation product. This is the second article written by Brendon Perkins on our PolyTrans software; the first review can be found here.

As an introduction to 3D data conversion, Mr. Perkins writes:

"If you work in 3D, chances are you rely on multiple software applications to complete your work - modeling, animation, rendering, image processing, and video editing apps; perhaps more than one of each. So it's interesting to note that no file format standard is accepted throughout the industry for exchanging 3D data among applications. On the other hand, it's not likely that one will emerge. Tool developers strive to create marketable advantages for their tools, and these advantages are reflected in, or implemented as, mutually incompatible file formats.

In lieu of a standard exchange format, most applications provide a limited set of import and export routines. But these routines usually don't provide a complete solution. In many cases, they don't account for intricate differences between formats that might help optimize models for the target application. Furthermore, they rarely deal with anything other than geometry. If you need a complete conversion that includes texture maps, animation paths, and the like, the usual import/export routines fall short.

The single fact is that converting between 3D file formats isn't a straightforward task, and vendors have little incentive to develop top-notch conversion utilities. Consequently, there's room in the market for specialized file format conversion applications."

As quoted from the article about PolyTrans, Mr. Perkins writes:

"PolyTrans is targeted at users who need quick and accurate [3D] file format translation, and there is no question that it offers the best import/export converters currently in existence. Developed over a decade, the latest version covers (these file formats). It supports meshed polygons with recursive holes, NURBS, bicubic patches, and quadrics; smoothing data with vertex normals; UV texture mapping coordinates, bump-mapping data with tangent vectors; lights; cameras; and even animation in a few cases."

"The user interface is easy to use and uncluttered, presenting the familiar four views. For each view, a toolbar pops up when you left-mouse-click over the title bar. These menus provide controls for such operations as zooming, panning, camera placement, and so on."

"The program provides a broad range of controls for optimizing conversions. All controls are provided with default values that work best under most situations. I tested the application with several large models in different formats, and the default setting worked well in most circumstances. In some cases, you may have to edit exported files by hand, but this is to be expected. It wouldn't be reasonable to expect perfect translations in all situations."

"Batch conversions are a very useful capability. This utility is versatile in the sense that it allows you to perform conversions on multiple files with different input/output formats in the same batch. The user interface makes it easy to specify the export format and control settings for several input files so that batch conversions can be defined quickly."

"The most notable addition to the program is the support for animation conversions available since version 2 of PolyTrans. 3DSr4, MAX and Lightwave can now exchange animation and scene files, complete with mesh, materials, textures, automatic bitmap conversion, lights and cameras [plus object and camera animation data]. According to Robert Lansdale, of Okino Computer Graphics, 'Animation conversion is a tough problem because the underlying mathematics used by the major animation packages are different and totally incompatible.' PolyTrans represents animation data using the native mathematics of the imported file. Conversion takes place during export using a keyframe resampling algorithm."

"NURBS files can be imported, cleansed, and even triangulated into polygonal meshes before you export to other file formats."

"PolyTrans uses a triangulation method called trapezoidal decomposition that's very good at reducing these [n-sided concave polygons] even when the polygons are improperly defined. Take, for example, a concave or convex polygon that's defined with a recursive hole and edges that overlap (not good). PolyTrans will triangulate the polygon to produce a well optimized and valid specification for the target format [Mr. Perkins goes on to make some example test triangulations of ill-defined n-sided polygons that have overlapping edges - PolyTrans triangulates them properly]."

The staff at Okino would like to thank Mr. Perkins for his second review of the PolyTrans software and for spending many hours talking with Robert Lansdale of Okino about all the "hard problems" involved with 3D data translation, such as the trials and tribulations of developing proper trimmed NURBS conversion software, of our long term R&D effort to study, develop and then provide animation conversion capabilities to our users, and of our forthcoming new developments in PolyTrans.