Clusters, Wires And Spline IK

Todays Class

Clusters
Wire Deformer
Spline IK

CLUSTERS

Clusters are a deformer that group individual or many vertices. It leaves a cluster object that’s easily accessible/keyframable.

Clusters are very simple. They only have a relative switch. This toggle means that the object moves with it’s parent or doesn’t. We might not want it to move with the parent to avoid double transformations particularly when some vertices are already skinned.

[iframely]http://www.youtube.com/watch?v=TXDFmQygg50[/iframely]

WIRE DEFORMER

The wire deformer is a good deformer to demonstrate as a lead in to spline IK. The Wire tool enables a NURBS curve to deform an object. Keep in mind to increase the falloff attribute to have it affect the whole object. The wire tool has limitiations in rigging, first it’s a bit slow and it has no control over twist. Also it will stretch volumes very easily.

[iframely]http://www.youtube.com/watch?v=B5pGrsimEqQ[/iframely]

Wire tool can be handy in modelling in a number of situations. Here’s a nice pro tip for moving eyes around with the wire tool.

[iframely]http://www.youtube.com/watch?v=xIGvcz9crPE[/iframely]

SPLINE IK

Spline IK give the rigger and animator a lot of control over a spline deformation and it’s used frequently in a number of situations. Tails, Spines, Tentacles, Pony Tails, Ropes etc.

Since Spline IK uses joints the objects must be skinned. It’s a good idea to match each joint to an edge loop and model most appendages like tails straight and let the animator take control later.

The following videos demonstrate the making of a spine rig with spline ik.
 

SPINE RIG OVERVIEW

There’s many variations of how to rig a spine. Here’s a nice simple example using Spline IK.

[iframely]http://www.youtube.com/watch?v=qVAMGLG7g3s[/iframely]

1. Creating the Spline Ik

Spline Ik can be created under

Animation Menu > Skeleton > Spline IK (options)

[iframely]http://www.youtube.com/watch?v=jldIaZzJhH4[/iframely]

2. Creating Clusters

Next we create clusters by selecting the spline IK curve and using the command…

clusterCurve;

Be sure to turn off “relative” for each cluster too.

[iframely]http://www.youtube.com/watch?v=RGFCbHjgScY[/iframely]

3. Adding Controls

In this video we add controls for a FK rig with individual cluster control.

[iframely]http://www.youtube.com/watch?v=fScoreU4fF4[/iframely]

4. Adding Advanced Twist Control

The Advanced Twist Control is found on the ik handle in the attribute editor

Ik handle tab > Advanced Twist Controls > Enable

World Up Type: Object Rotation Up

Up Vector: 0, 0, 1
Up Vector 2: 0, 0, 1

In the two object box’s copy and paste the names of each object which will define the twist.

[iframely]http://www.youtube.com/watch?v=d7s_se1z7x4[/iframely]