This is where animation controllers come into play. You canвЂ™t simply create a single animation that can somehow tell what your player is doing at any given time. You need animations for the character in a crouching position, crouching and walking forward, sprinting and moving forwards, walking and moving left, and more. Each of these states requires a custom animation. Maybe the player can crouch and move in any of these directions at the same time. Maybe the player can also run in any of these directions. In a game, maybe you allow your user to move a character forward, backward, left, or right. In a game, this isnвЂ™t an option unless youвЂ™re rendering non-playable cut scenes. In a 3D animated film, the modeler animates every single frame of the film in a very specific way. The main difference between a video game and a 3D animated film, for instance, is that a video game must be adaptable to a wide variety of inputs and conditions. Games heavily use 3D and 2D animations for models and sprites. If youвЂ™ve done any 3D modeling youвЂ™re likely familiar with 3D animation. It will return to white when the user presses spacebar again. Specifically, we will make an animation that will make a 3D cube red when the user presses spacebar. This controller will be able to play an animation when the user presses a button on their keyboard. In this Unity tutorial blog, IвЂ™m going to provide step-by-step instructions to create a very simple animation controller. In general, developers will utilize animation controllers (Unity calls them animator controllers) to handle which animations to play and when to play them.

Unity 3D has some great tools for handling animations.

Character animation tutorial