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.
Collada (COLLAborative Design Activity) is an interchange format for interactive 3D applications. Originally developed by Sony Computer Industry, now it is managed by the Khronos Group, a member-funded industry consortium, which now shares the copyright with Sony, Recently Collada has been well adopted by ISO as a publicly available specification, ISO/PAS 17506.
It is an XML-based schema that allows data exchange among 3D Digital Content Creation tools, such as SketchUp, Maya, 3ds Max, and Rhino. COLLADA files have the *.dae file extension, which stands for digital asset exchange.