OBJ is a geometry definition file format (.obj extension) first developed by Wavefront Technologies for its Advanced Visualizer animation package.
The OBJ file format is a simple data-format that represents 3D geometry alone — namely, the position of each vertex, the UV position of each texture coordinate vertex, vertex normals, and the faces that make each polygon defined as a list of vertices, and texture vertices.
Vertices are stored in a counter-clockwise order by default, making explicit declaration of face normals unnecessary. OBJ coordinates have no units, but OBJ files can contain scale information in a human readable comment line.
A PRT file is a model part file saved in a three-dimensional model format used by Unigraphics, a 3D CAD program. It contains surface and solid information for a single part. PRT files are saved in a binary format, similar to an Alias wire model and an SDRC (Structural Dynamics Research Corporation) model.
A CAD file is an output of a CAD software, containing key information about the designed object: its geometry and topology representation, 3D model hierarchy, metadata, and visual attributes depending on the format of the file.
Read moreIn the ninth part of the series, we take a look at the effectively standard format for 3D graphics
Read moreCAD Exchanger imports and tesselates FBX, glTF, OBJ, PLY, and STL files, making them ready for further optimization by RapidCompact.
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