What Is Character Animation?

table of contents

When we talk about character animation, we mean to impart anthropomorphic motion to some object. It is not necessary that it be a human or animal character; virtually anything can be a character ”gas pumps, mushrooms, even sacks of flour have been animated as characters. However, in nearly every case, the animator uses various deformers in Maya to impart animal motion and intelligence (and, if the animators are successful, emotion and identity). Obviously, you can animate robots and other rigid objects in a way that still conveys that they are characters . This chapter, however, is concerned with organic, bendable characters ”flesh and bone.

Deforming objects in a way that mimics nature is usually more complex than other deformations in Maya. Typically, if you are bending or twisting something, you can add the deformer and quickly get the mechanical result you desire . However, animating something with an implied skeleton overlaid with muscles , which are overlaid with skin, which is overlaid with clothing, requires a lot more adjustment to get a result that is anatomically believable. For example, a human elbow bends differently from a neck joint. Initially, all of your Maya joints will allow universal rotation. Further, real muscles "flex" when contracted, creating a bulge that is more evident for some muscles than others. Also, localized joint movement will pull and relax nearby skin in various ways. A torso doing a "crunch" will make skin do something different from the skin on fingers bending into a fist. Finally, all these variations will be different from character to character; a scrawny old wizard would be set up quite differently from a plump baby or a bodybuilder.

The general approach we'll take in this chapter is to first create joints inside the character to provide articulated movement where we will animate the character. Usually you only add joints where you will want to bend the character, so a shoe- wearing character will not have toe links for each toe. Next, these joints are connected together to create a complete linked skeleton, and adjusted to fit properly within the areas they will deform. Note that the joints themselves do not render, so if a joint protrudes through part of the character, it does not necessarily require adjustment.

Next, Inverse Kinematics is applied where desired, usually to each link chain that connects to the root joint. On a typical biped, the arms, legs, and spine/head would be connected with IK so that you can crouch the character by simply pushing the head down. To ease the animation process, we'll also create easy-to-select handles as part of our character rig.

With the skeleton now behaving in a controlled manner with IK, the character geometry is then bound to the skeleton as a smooth or rigid bind. The procedure from here varies depending on the type of binding, but the goal is to get muscles to flex and joints to bend in the desired way. In this chapter we'll use rigid binding, which then leads to using Flexors to adjust local joint bends.

With the character now set up for animation, we can set keys to make it move. In this chapter, we'll set the character to take a couple of steps forward. With IK already applied, simply posing the hands and feet will make the rest of the character move appropriately.

Maya's Trax feature lets you take any motion set from a defined character and apply it as a "clip." We'll explore this by taking a single walk cycle and using it to make the character walk for some distance.

Finally, we'll explore facial animation with blend shapes . Starting with a neutral face, we'll sculpt a new facial pose and then blend this pose with the neutral pose over time.



Maya 4. 5 Fundamentals
Maya 4.5 Fundamentals
ISBN: 0735713278
EAN: 2147483647
Year: 2005
Pages: 201

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