OBJ files are used by wavefront's advanced visualizer application to define and store the geometric objects. Backward and forward transmission of geometric data is made possible through OBJ files. Both polygonal geometry like points, lines, texture vertices, faces and free-form geometry (curves and surfaces) are supported by OBJ format. This format does not support animation or information related to light and position of scenes.
U3D (Universal 3D) is a compressed file format and data structure for 3D computer graphics. It contains 3D model information such as triangle meshes, lighting, shading, motion data, lines and points with color and structure. The format was accepted as ECMA-363 standard in August 2005. 3D PDF documents support U3D objects embedding and can be viewed in Adobe Reader (version 7 and onwards).