Background and Goals

The model for the Shapeshifter was provided by Ashton Anderson of Lightspire Games. The rig is designed to perform most natural human movement with subtle exaggeration. The goal is to make an intuitive rig with good deformations that can be animated easily and quickly.

Approach

The rig was approached with many ideas that were brought back with me from Siggraph 2008. Like in Horton Hears A Who, I wanted my controls to be separated from bind in the rig. This would allow me to make changes to the controls and not lose my bind. This was a valuable idea as many of the features on the rig were changed after it had been bound and no time was spent going back to fix the weighting. Next, I wanted the rig to switch from IK to FK and back easily and have many visual clues for the animator to follow in order to make this happen. The idea of ghosting the controls and geometry that was being switched was also first observed by me at Siggraph. This allows animators to pose the IK and FK simultaneously and then animate the IKFK Switch to get the poses in between rather than trying to match the IK to the FK without any jumping. Lastly, I wanted the rig to be realistic in motion. The muscle system applied had been an idea in my head for me for months. I applied those ideas to my model as well as more strict limitations to the controls to create a more solid and believable rig.

Features

IKFK Switch with Ghosting - The Shapshifter has the ability to blend smoothly between IK and FK on all four limbs. There is an option to ghost draw all of his limbs and their controls so that the animator can pose both IK and FK skeletons at the same time. This will provide them with an easier means of blending between their IK and FK animations.

Hand Orientation - When in IK, the hands of the rig are controlled through two controls. One is for position while the other is for rotation. The rotations of the hands can be oriented to either the forearm or the world using the hand orient channel in the rotation control.

Space Control - The translations of the hands can be reparented in four different locations on the rig. The world (Provides normal IK function), the back (Keeps hands oriented to the upperbodys rotations), the hips (Allowing the hands to be rested on the hips), and the head (Allowing the hands to be rested on the head). When switching from space to space in the middle of animation, the control will not hold its current position. Therefore, it is recommended that the user use the spaceSwitcher script provided with the rig that will keep the position of the arms upon switching from space to space.

Face Controls - The rig is equipped with face controls in multiple locations. There are channels under the head curve on the rig itself, as well as a Gui inside the viewer. There are cameras set up for facial animation. The faceControllerCam houses the interface gui, and faceDeformedCam shows the final face deformations. The rigs controls are two-way connections using shape parenting so the channel controls will update the Gui and the Gui will update the channels as well.

Face Poses - Because of the nature of the face control rig, preconceived blendshape vowels or mouth shapes are not possible without locking out the channels of the controls used in the two-way shape connections. Therefore, in order to more easily reach complex face positions, the script facePoser provided with the rig allows animators to choose which parts of the face positions to save out to a file and load into their pose library for multiple usage throughout the life of rig and their animations. Simply, File > Save Pose to save a .fpf (Face Pose File) to the users scripts directory in a subfolder called facePoser. Clicking File > Open Pose allows the user to find existing .fpf files and load them into their Gui and apply them to the face. Future plans for this script include mirroring poses across the face with either replacing or matching on the opposite side as well as blending between existing saved poses to create mixture poses.

Keyframe and Selection - In order to make it easier to key and select sections of the body, the selectandkey script is provided with this rig. It allows the user to select sections of the controls on the rig for either switching between spline or other forms of animation curves in the outliner and also keyframe all of the keyable attributes on those controls.


Muscle System - The Shapeshifter is equipped with a functional, full-body muscle system designed by myself. The muscles squash and stretch when animated and have a controller to modify their dynamic jiggle above the models head. This provides an extra level of realism to the animation when the solver is turned on for the final render.