Unity is a game engine made by Unity Technologies. It supports more than 25 different platforms. This engine is used mostly to design three-dimensional, two-dimensional, virtual reality, and augmented reality games. It has been adopted not only by video gaming industry, but also by film, automotive, architecture, engineering and construction.
Unity enables users to develop games and experiences both in 2D and 3D, and offers a primary scripting API in C#, as well as drag and drop functionality. Within 2D games, Unity provides importation of sprites and a 2D world renderer. For 3D games, it allows specification of texture compression, mipmaps, and resolution settings for each platform it supports. Also, it provides support for bump mapping, reflection mapping, parallax mapping, screen space ambient occlusion, dynamic shadowing, render-to-texture and full-screen post-processing effects.
OBJ (or .OBJ) is a geometry definition file format first developed by Wavefront Technologies for its Advanced Visualizer animation package. The file has been adopted by many 3D graphics application vendors.
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.