Characteristics of Unity is:

It is a multi-platform game engine with features like ( 3D objects, physics, animation, scripting, lighting etc.)

► Accompanying script editor

► MonoDevelop (win/mac)

► It can also use Visual Studio (Windows)

► 3D terrain editor

► 3D object animation manager

► GUI System

► Many platforms executable exporter Web player/ Android/Native application/Wii

In Unity 3D, you can assemble art and assets into scenes and environments like adding special effects, physics and animation, lighting, etc.