Maya Software - Part 2 - Modeling and Overview of Animation


NURBS, polygons and subdivision surfaces (or SubDivs) are available in Maya.
Polygons are a widely used model medium due to its relative stability and functionality. Polygons are also the bridge between NURBS and SubDivs. NURBS are used mainly for their ready-smooth appearance and they are used in Dynamics because they respond well to deformations.

SubDivs are a combination of both NURBS and polygons. They are ready-smooth and can be manipulated like polygons, providing the artist with an instant representation of a smoothed polygon. Maya's hair cannot be applied to Sub division polygons.

Overview of animation

Keyframe Animation

The model is placed in a starting pose or position, and a keyframe is set. Some frames later, another keyframe is set, and the model is moved as desired. This process is repeated as many times as needed. The animation software interpolates the motion needed to move the model smoothly between the keyframes. What this means is that if the animator keys a box, and moves the box across the room in the next keyframe, when the scene is scrubbed or viewed, the box will glide across the floor instead of jumping from frame to frame. This applies to anything in the scene - moving fingers, eyelids, moving lips, etc.

Nonlinear Animation

After animating a character with keyframes or motion capture, its animation data can be collected into a single, editable sequence. This animation sequence is called an animation clip.
In Maya, there are two types of clip: source clips and regular clips. Maya preserves and protects a character's original animation curves by storing them in source clips. Source clips are not used to animate the characters. Instead, copies or instances of source clips called regular clips are used to animate the characters nonlinearly.

Moving, manipulating, and blending regular clips to produce a smooth series of motions for a character is the basis of nonlinear animation. The tool with which all these aspects of a character's nonlinear animation can be managed is the Trax Editor.

Path Animation

A path animation controls the position and rotation of an object along a curve. An object must first be attached to the curve for it to become a path curve. Motion paths can be generated by animating objects using motion path keys.

Motion Capture Animation


Skeletons are hierarchical, articulated structures that let the animator pose and animate bound models. A skeleton provides a deformable model with a similar underlying structure as the human skeleton gives the human body.

Just like in the human body, the location of joints and the number of joints you add to a skeleton determine how the skeleton's bound model or `body' moves. The process of binding a character to its skeleton is called "Skinning". The process of making a skeleton or bones, refining the joints, using IK or FK, putting handles on the joints so animators can manipulate them, and over all making the model ready for animation is called "Rigging"

Forward Kinematics

Forward Kinematics (FK) is an animation method that involves moving each joint without the restriction of an expected final position. Thus, the 'goal' is to move a joint (or series of joints) as desired, and the final pose is a consequence of those movements. Forward Kinematics is often used for finely-tuned joint movement (such as hands & fingers), as it allows for more complete control over posing.

Inverse Kinematics
The reverse of Forward Kinematics, Inverse Kinematics is a method that involves defining a final pose, and generating joint movement as needed to reach that pose. Thus, the 'goal' is for all joints to be in a final pose, and the individual joint movements are a consequence of getting to that final pose. Joints must have carefully defined limits to their possible motion for Inverse Kinematics to work well, or the joints can end up 'flopping' before reaching the goal pose. Inverse Kinematics is often used for large limb movement (such as walking, reaching, etc.).

Full Body IK Solver

When Alias bought Kaydara, Maya got an upgrade, from Kaydara Motion Builder, with a full body IK solver (FBIK Solver) which simulates real body kinematics. The package comes with a biped and a quadruped FBIK sample.

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