An Essential Introduction to Maya Character Rigging

by Cheryl Cabrera

Chapter 5Skeleton Setup for a Biped

Character:Joint Placement

Characters by Faye Helfer, Nathan Englehardt, Dan Nichols, Nick DuBois, and Mark McDonald.

Traffik by David Bokser (2003).

Joint Placement Workflow.

The hierarchy of a joint chain as seen in the Hypergraph.

Frog Ballerina by Sarah Pitz.

Create Reference can be found under the File menu.

The Create Reference options window.

The Reference Editor.

Replace Reference and Remove Reference can be found in the Reference Editor under the Reference menu.

Import Objects from Reference can be found in the Reference Editor under the File menu.

Proper Character Placement for rigging.

The image of the character on the left looks similar in scale to the image of thecharacter on the right. However, on closer look, the character on the left is actually

the scale of the image in the middle. Make sure that your character is not too small, asit will cause problems with some tools and when animating.

Shading X-Ray Joints.

The Joint tool can be found in the Animation menu set (F2) on the keyboard under the Skeleton menu.

Two joints are connected visually with a bone.

The long bone radius changes the size of the joint based on the distance it is from the following joint. Changing the long bone radius to 0.5 will prevent this.

Joint Size options.

The Cartesian coordinate system and its point of origin.

A sphere that has been created at the origin and is in World space.

A sphere that has been moved from the origin and rotated shows a different coordinate system called Object space.

A sphere (left) that has been moved from the origin and rotated with its parent shows a different coordinate system called Object space.

The same sphere (right) showing Local space.

Local rotation axis set to XYZ on a vertical joint chain, where the axis does not line up from one joint to the next.

A spine chain prepared for Forward Kinematic control.

A spine chain prepared for Inverse Kinematic control.

Displaying the Local Rotation Axes in Object Mode requires that each and every joint be selected.

Displaying the Local Rotation Axes in Component Mode requires that the top of thehierarchy be selected to see all of the Local Rotation Axes for that hierarchy.

Moving a joint into place will also move any joints below it in the hierarchy (left), unlessthe move pivot mode is toggled on by pressing the Insert key on the keyboard (right).

Rotating or scaling joints into place requires the Freeze Transformation command to reset the values.

Warning signs for non-zero rotations appear during the reorientation process if the joint’s transformations have not been frozen.

Orient joint option box.

Manual rotation of a joint’s Local Rotation Axis is possible for fine tuning joint rotation.

A MEL command can be used forprecise rotation of the axis.

Little Billy by Sean Danyi (2003).

An Essential Introduction to Maya Character Rigging

by Cheryl Cabrera

Assignment 5.1: Creating a spine, head, and neck

skeleton

Setting all four view panels to X-Ray Joints mode.

The Joint tool option settings.

Adjusting the display size of the joints.

Positioning and renaming the spine joints.

Placing the pelvis joint.

Placing and renaming the neck and head joints.

Placing and renaming the jaw joints.

Placing and renaming the tongue joints.

An Essential Introduction to Maya Character Rigging

by Cheryl Cabrera

Assignment 5.2: Creating an arm and hand

skeleton

Placing and renaming the arm joints.

Repositioning the arm joints.

Placing and renaming the clavicle joints.

Repositioning and reorienting the clavicle joints.

Placing and renaming the middle, index, and ring finger joints.

Placing and renaming the thumb and pinky finger joints.

Repositioning the finger joints in the perspective window.

Reorienting the joints in the hand.

Adding the left prefix to the arm chain.

Establishing the mirror direction as a reflection. Mirroring on the XY (left), Mirroring on the YZ (middle), and mirroring on the XZ (right).

The mirror joint options.

An Essential Introduction to Maya Character Rigging

by Cheryl Cabrera

Assignment 5.3: Creating a leg skeleton

Placing and renaming the leg joints.

Repositioning the leg joints in the FRONT orthographic view panel.

Mirroring the left leg to create the right leg.

An Essential Introduction to Maya Character Rigging

by Cheryl Cabrera

Assignment 5.4: Test the Joint Placement

Selecting all of the joints.

Changing the geometry layer to normal.

Creating a skin deformer.

Changing the geometry layer back to reference.

Good deformations on the character’s shoulders on the left, and bad deformationscaused by improper joint positions on the character’s shoulders on the right. The rightimage shows two common problems. The left shoulder (right image) has a joint that isplaced too far into the bicep. The right shoulder (right image) has a joint that is placedtoo far into the body.

The area around the waist may look like it is cracking and indenting. This is not a jointplacement issue, but rather, the skin deformer needs to be smoothed in this area

(covered in Chapter 8). The elbows and the knees are pinching because there are notenough divisions in the geometry to make a smooth bend.

Think about the difference between a regular straw and a flexi-straw. A regular straw pinches when it bent (left). A flexi-straw can bend

more smoothly because of the added divisions allowing it to bend (right).

Repositioning joints in the shoulder.

An Essential Introduction to Maya Character Rigging

by Cheryl Cabrera

Assignment 5.5: Verifying the Local Rotation Axis

The proper Local Rotation Axis for the joints.

The proper Local Rotation Axis for the right arm and leg.

Displaying the Local Rotation Axis in component mode.

Rotating the thumb Local Rotation Axis into position.

Visualizing the direction of the Y axis by using a pen.

Verifying that the wrist Local Rotation Axis is straight.