So you're looking to be an animator, but people aren't really your thing, huh? You want to be the one to make the next Lion King, eh? Well, then this is the guide for you. Animals are a bit more tricky than people, mainly because you have 100% more legs to work with than humans most of the time, sometimes its even 300%, I think, I don't know man, animals are weird. But I'm lucky enough to have very basic and somewhat limited knowledge on the subject of how they move and things, which is also weird, but you know, what can you do. To grasp how animals move, theres 4 essential steps. Anatomy, key frames, movement of the limbs and movement of the rest of the body as it works with the limbs. Some of that sounds a bit daunting, but I assure you, once explained, its not at all as hard as it seems. Lets get started shall we?
Step 1: Spooky Scary Skeletons
Before you can begin to animate any animals, it's a good step to get familiar with the way their skeleton is structured. The placement of bones and joints, quite obviously, has everything to do with the way they move. The locations of their shoulders, elbows, wrists and so forth map out limitations to their movement and flexibility, or they could explain why the animal is so flexible, dependent on how they are built. Luckily, most animals share pretty common basic structures, if they are of the four legged variety of course. If you put a dogs skeleton and a cats skeleton side by side, you should notice that the way their legs are built share many common traits. Their legs bend the same way and share the same basic structure, for example. However, its the little things that explain how they move. The legs of a cat have much more bend to them, they have less ribs that makes them more flexible, their spines are longer and more flex to them. Simple things like that tell us that cats move with more prowess and grace than a dog would, who are built more so for power than cats. This means that when they run, though they have similar cycles due to the similarities, a dog will move with much more mass, for lack of a better word, than a cat. The cats flexiblility makes it move with much fluidity than a dog, whose bulk makes it run roughly. The position of their joints and the length of their bones also have a lot to do with how they move. To stick with our example animals, lets examine the front legs of both a cat and a dog. Dogs will typically have a shorter humerus than a cat will, as well as a longer scapula. The makes their movement less noticable in the shoulders, while you can visibly see the shoulder of a cat as it walks. To wrap this up, skeletons are important. Try as you might, you can't move in certain ways unless your bones are built for it.
Step 2: Don't Forget Your Keys, Dear
Animation is split into two basic groups. One is the key frames, the point in the animation where the movement is most drastic from the last frame. Two is inbetweens, which move ever so slightly each frame to link the key frames together. For all upcoming examples, I will be using this animation of a cats walk cycle that I created for the purpose of this instructable as an example. For walk cycles, the animation will usually consist of 4 frames. The two contacts (the legs extended in front) and the two passes (the back and front legs in the midst of passing the opposite leg). This is how most animals walk. These are the backbone to your animation. Without getting these right, no matter how good the inbetweens, the cycle will look off. Key framing is what animation is quite literally built on. If you have any trouble keying out these frames, try to look at videos or stock photos of the animal you are animating. No matter how talented you are, it's always good to have references.
Step 3: Knees Are Weak, Palm's Are Sweaty, Arm's Spaghetti
Animals dont move their front and their hind legs simultainiously. Infact, usually when the front legs have just entered into their contact stage, the hind legs have just started their passing stage, meaning they either never touch the ground at the same time or they ever so briefly do, depending on the animals in question. Thats the main thing you have to keep in mind while moving your animlas legs.The second is how they carry them when they are moving. The front legs curl in for the pass and then swing forward for the contact, some individuals even waiting until the last second to extend their paw to meet the ground, adding a cute little flick to the end of it. The hind legs will pull in for the pass and then stretch outwards for contact. And as mentioned before, animals are still individuals, and not every single one will walk the same. They might add the previously mentioned flick, they might walk very loosely, hardly pulling or curling their limbs in, or they might walk extra tightly, the legs pulled in very neatly whenever off the ground. Their movements also depend on the situation or environment they're in. Like when you put little booties on a dog and they pretty much suck their legs back into their bodies they're lifting them so high. Figure out how your animal moves and see what kind of personality you can give it in its walk.
Step 4: Move That Body, Move That Body, Make Sure You Don't Hurt Nobody
If you look at the cats shoulder and rump as I animated it, you'll likely notice that they aren't static. The shoulder rises and tenses as the leg it is connected to is in contact, the highest point being when the leg is straight, and the hip does the same. Making sure your animals body moves with its legs is extremely important, as thats the only way the motion will seem fluid. If the back of the animal is completely still and seems to be frozen whilst the legs are moving makes your animation either seem like something is horribly wrong or just alltogether unnatural. Your bones are always moving together, almost never on their own. They all interact and move in sync, and the same goes for animals. In fact, the more dramatic the movement of the shoulders or the hips the more interesting it is to look at your animation and watch it. I went more realistically with my animation for the sake of this instructable, but that doesn't mean thats the only way to do it. The over-exaggerated movements found in cartoons is what makes them so fun to watch, so don't be afraid to get a bit crazy with it.
Step 5: And That Is How We Do It
Well, there you have it folks. You now know a beginners clutch of knowledge on how to animate furry beasts. Remember to keep practice up and not to get discouraged. Every master was once a beginner and you're no exception. Heck, you'll probably be running circles around me on your animated steed before you know it.