Key principles of game animation and CGI

In this article we talk about the main principles of game animation, which all aspiring artists should learn. In particular, we pay attention to the aspects that make animation realistic, and also explained the differences between CGI animation and game animation.

Key principles of game animation and CGI

Difference between CGI animation and game animation

The main difference between CGI animation and game animation is that it is created in advance, so all the compositional work is initially planned.

Both game animation and CGI animation use the same principles, but their application is slightly different. With CGI animation you can control exactly what the audience sees. The CGI animator's main job is to make everything believable and entertaining to watch (obviously, this applies both to in-house designers and animation outsource developers).

In game animation, it is the user who controls the camera, so it is important to take care that the game looks good from every angle. In addition, the animations themselves should run as soon as the user presses a button – this means that movements should be made immediately, and the controls should feel fast and responsive.

Game animation also differs from CGI in that it creates a large number of animations for different actions and then stitches them together using code in the game engine.

For example, a very simple jump typically has four animations that are coded to play one after the other after the jump button is pressed: from a resting state, the character moves to a pushing position off the floor, then a landing that loops until he touches the surface, and then the resting animation comes on again at the end.

The same concept is used for everything in video games. Many animations have a separate start stage, like the example mentioned above. But some have to be very fast, so they skip this stage. For example, you have to swing the big sword first and only then strike because it's heavy. With a knife, however, you can start the attack right away because it is light.

Planning

The first step in creating an animation is planning. For example, in the game Oasis, the author wanted to make the Enn character's gait look nice and convincing. To do this, the animator had to do several things:

  • a looped idle animation;
  • an animation of the transition to running;
  • a 90-degree turn to the right;
  • a 90-degree turn to the left;
  • turn to the right by 180 degrees;
  • turn left to 180 degrees;
  • looped animation of movement with a step;
  • stop animation.

All of this was necessary to create a movement system that would allow the character to move depending on where the player was pointing it.

The author also wanted the jumps and landings to always look different and depend on two variables: how long the character is in the air (AirTime) and whether he is moving. The solution was the following animations:

  • looped running and stepping;
  • a transitional start animation from step to jump;
  • transitional start animation from running to jumping;
  • looped fall;
  • transitional landing and tripping animation;
  • transitional landing and roll animation;
  • transitional superhero landing animation.

Based on this, the author created BlendSpace, which is a graph that tells the character which animations he should perform depending on the values of certain variables. This type of graph is a specific feature of the Unreal Engine, but the concept is applicable to various game engines.

The rest is the adjustment of the animation according to certain events that take place during the game.

Key principles

When creating animations, it is important to consider certain principles. First, you need to take into account the setting of the character. You can start with the starting pose and assess all animation – does it reflect the effect you want? Is it easily identifiable? Does it seem interesting? If not, you need to keep trying until the desired result is achieved. You can also place poses on the timeline to get a rough idea of the timing and to check the animation in the engine.

At first, the animation is very crude, but it gives you an idea of what the movement will look like. Next, you need to transfer it to the Unreal Engine and test it to see what it looks like from the player's point of view. After that, you can move on to the next step: inbetweens. The point of this stage is to adjust the movements between the basic poses that were made earlier-they begin to form arcs and help refine the timing of the movement.

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At this stage you can gradually polish the animation – add weight to it, work through each movement, and so on. The author notes that for the superhero landing, it was important that the character fall quickly and land in a certain pose. Timings are incredibly important to achieve a satisfactory result.

For games, timings are usually very fast. If you slow down the animation too much, the result is quite clumsy. Once a button is pressed, something has to happen. To make a jump, characters usually crouch down very quickly and then push off the ground almost instantly. 

Pose building is important in both CGI animation and game animation. In stories with short animation timings, it's important to find ways to convey movements as quickly and intelligently as possible. The character's pose tells you what's going to happen, what's happening now, and what's happened in the past.

Silhouette is very important for good readability of movements. For example, if someone makes a punch, the viewer should definitely see a fist. Even if a character pulls something out of his pocket, it must be absolutely clear – if it's not, people might miss where the new object came from.

The solution to this problem is to always make it clear in advance what's coming next. In a situation with an object in the pocket, the player should see the character's hand move up before it goes down into the pocket. And it's important to do this even if people don't necessarily move that way in real life.