The Shared Skeleton Rigging Tool

     This project began with my thought that one skeleton; I call the "Shared Skeleton", could be used for both Motion Capture and Key Frame Animation, allowing an animator to freely choose one of the methods, depending on the project's characteristics and needs. An animator would have the option to switch from Motion Captured footage to a manual character setup, without having to rig and bind again. Every character would be able to share the same skeleton structure, allowing animations done with the 'Shared Skeleton' to be transferred to any character with the skeleton.
At the beginning of the project I created an animation pipeline (Fig 1), and I wrote what I needed to do and what I wanted. After drawing it, I figured out that if I only use one skeleton structure, I can build an animation database, allowing me to save animations and reuse those where and whenever needed. Much of the motion data can be used for Massive software for crowd shots or many Visual Effects and Animation Studios, especially Game Studios. In fact, many studios make uniform animations for like running, walking, and jumping.

                                                                                           The Animation Pipe Line (Fig 1)   

The Skeleton Structure from Motion Builder(Fig 2)

The first step was to match the correct joint labels from the Motion Capture data. I selected Vicon Blade and Autodesk Motion Builder 2011 to test it because Blade Vicon and Motion Builder are widely used in Visual Effects, Animation and Game Industry, and they are cross compatible with each other. They also automatically recognize the skeleton's basic structure of what I wanted.
The skeleton structure came from Motion Builder help files, and it has been used since motion capture was initially made. I can get amount of Motion Capture data and information from everywhere if I make the shared skeleton with this labeling rule. I am also able to use Full body IK system in Motion Builder with the skeleton structure. I decided to build my skeleton structure following the rule of the Motion Builder's labeling.

However, joints were not enough to make manual key frame animation. I wanted to have a full functional manual key frame character setup as I use Motion Capture system. I started researching many character setups, how they work and what they consisted of. Eventually, I decided to make stretchy arms/legs and bending arms/legs, and a FK/IK switch system.
I added more joints between the arms, legs, and spine, to make it follow the Motion Capture rule. I figured out that I needed to make a tool for this project, in order for it to be more user-friendly, because of the complications involved. I began making my rigging tool while compiling all of my thoughts, and I called this the Jin Rigging Tool, temporally (Fig 3)


This is Jin Rigging Tool (Fig 3)                                                   

After building the skeleton, I needed to orient the joints so I made orient joint tool into the Jin Rigging Tool as an additional function. Finally, I got the correct skeleton labeling with enough joints fixed for orienting the joint (Fig 4). I have tested this skeleton in Motion Builder with Motion Capture data, and it worked fine, and I could use Full body IK system in Motion Builder (Fig 5).


            This is the shared skeleton (Fig 4)                                       The shared skeleton in Motion Builder with Full body IK solver (Fig 5)

    Second, I had to make a manually setup a character Maya. I wanted to make a full functional character setup, so I started making character setup with the shared skeleton by adding additional functions. The first function is to switch FK/IK arms and legs. For this, I used more than three arm and leg joints with point and orient constrains. I gave the FK/IK controller to a whole arm controller. The second function is to stretch arms and legs. For this, I used RP IK solvers, and some of the utilities in Maya node such things as condition and multiply. Also I gave stretchy function to all arm and leg controllers as well for flexible animation, depending on how realistic the animator needs their character to be. Third, I added bending function for arms, leg and spine. This function adds a lot of flexibility in character animation. I gave two controllers in between arms and legs so animators can manipulate the bending arms and legs with the bending controllers. Overall I made some additional functions that animators would like. For instance, an independent tool for 'insert joint' and ribbon stretchy skeleton so animators can add more joints for additional structure like tails and wings.

This is for the manual character setup and test movie.

    Finally I made an attaching skeleton tool. For using motion capture and the manual character setup without rigging and binding again, an animator needs to have the binding independently after making the skeleton by saving as a MA file. Then I import the binding character with the shared skeleton into the character setup or Motion capture system. The next step is to attach either the Manual Character Setup or Motion Capture data. I created the attaching and detaching tool so animators can attach their character to either the Manual Character Setup or the Motion Capture.

    Swiching between Motion Capture and Key Animation
                       and sharing animation to different structured character built with the Shared Skeleton

    I was able to save the motion files and reuse them to other characters that are built with the shared skeleton. Also, every character could be integrated with one skeleton structure through the Jin Rigging Tool. Additionally, I could save the motions as FBX files, and I could go to any 3D software that supports FBX file format and use the data. As a result, I was able to build the pipeline in (Fig 1). I hope this rigging tool can save money and time for many studios. This tool is currently being beta tested by Baba Studio, an Animation Studio in Korea and I am receiving feedback. In the future I will add more features like an IK hair system and weight tool.

Animations completed with the "Shared Skeleton" can be applied to other 3D Software Programs

Working the Shared Skeleton in 3D Software Programs



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