group placement - foot ctrl setup 3

Q.
1)Why are there ik handles connecting the ankle to the ball joint and the ball joint to the toe joint, when they are two joint chains (ik handles need 3 joints in order to calculate the movement)?

2) Why group the IK handle to itself and not the ball joint to itself

A.

1) Because the IK handles control the rotation of the joints, and keep the angles of relative proportion when rotated at the ankle joint.

2) IK handle again maintains the length and the angles of the foot rig so it behaves naturally. When a joint chain has an IK attached to it, you can still select the joint and it will behave in a forward kinematic fashion, so if you group the joint and not the IK handle, the group will behave like a forward kinematic rig. (see illustration below for example)

group placement - foot ctrl setup 2

Joints can now be translated from the heel RIG, and move about quite nicely, so time to create a couple of extra pivot points for the toe-tap, toe-rotate and ball-rotate, which will be articulated through the expression editor, set driven key menu and the connection editor (essentially three different ways of of establishing relationships between nodes).

The book instructs you group the toe_IK to itself, creating a "null node" - a node that exists above the toeIK handle with a different pivot point.



When the null node is rotated in the X the foot rotates correctly from the ball joint.

group placement - foot ctrl setup

screen shot taken from following the rigging tutorials in "3D Character setup". At this stage in the tutorial I have created a simple leg setup with a duplicate joint arrangement ctrl parented in the opposite direction and named "RIG" The IK handles are parented to the RIG, which in turn is connected to the original joints via the end effectors.

Inverse Kinematics

Been trying to establish a comprehensive understanding of Inverse Kinematics, and how it's applied in other disciplines.

Syg Mead

Syg Mead - produced high quality visuals for films like Blade Runner and Alien. Found an interesting paragraph from a blogger who'd attended a Syg Mead seminar in SF. During the Q&A he asked him:
"how far he went on a design to make it technically believable."
His advice was
"to design with the story in mind and stay consistent with it"

Useful advice.

maya live tutorial

tutorial - matchmove with Maya Live from juri ciani on Vimeo.

shoulder rigging

realistic method for rogging the shoulder using condition and multiply divide nodes. Still haven't found a satisfactory solution for the previous multiply divide quandry i was experiencing, but set up a post on the rigging101 forum, to which the site administrator has replied. Ho Hum.