This is because not all of them can seamlessly deal with freeform surfaces that are defined using mathematical equations. It is also worth mentioning that not all 3D software applications can open OBJ files. Moreover, the OBJ file can contain comments, as shown in the screenshot below.Įxample of an OBJ file for a cube that has different colors ( source) These elements can be placed into groups – represented using the keyword “ g ” – for convenience or to promote seamless rendering. That said, the OBJ files that are encountered most frequently only contain polygonal faces and are therefore defined using the v and f keywords.

” Other keyword representations include p (for a point), l (for a line), curv (for a curve), curv2 (for a 2D curve), and surf (for a surface). For instance, geometric vertices are represented using the keyword “ v. The format specifies these elements using keywords. Specifically, the equations denote the polygons’ elements, such as geometric vertices, lines, points, faces, curves, and free-form surfaces.

These characters are contained in mathematical equations that represent tessellated polygons. OBJ is an ASCII-based format that represents properties of 3D objects using a character set that contains numbers from zero to nine, English letters from A to Z, and special characters such as decimals. But as we have detailed below, not all 3D software can open OBJ files. Currently, multiple 3D software applications are capable of opening it.

And it is this neutrality that has made the file format popular and somewhat universal. In the mid-1990s, however, Wavefront Technology relinquished control of the definition, revision, and distribution of the OBJ file format, effectively making it vendor-neutral. The file format was also intended to facilitate the transfer of geometric data between the Advanced Visualizer and other applications. OBJ, also known as Wavefront OBJ, is a shortened version of the word ‘Object.’ First developed, defined, and used by Wavefront Technologies beginning in 1990, OBJ was initially intended to define the geometry and other properties such as color and texture, particularly in Wavefront’s Advanced Visualizer. What is OBJ File Format? History of OBJ File Format Factors to Consider when Choosing a Good 3D Slicer for OBJ to G-Code conversion.

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