Based on SIGGRAPH's Automatic Rigging and Animation of 3D Characters [Baran SIGGRAPH07].
Algorithms based on Pinnochio system described in paper.
Manual rigging requires time-consuming placement of joints to make skeletal animation look realistic. Along with my friend Steven Knipping, we propose to solve this by implementing a tool that will be able to auto-rig any character/mesh the user creates. Meshes must be restricted to a standard, predictable pose – for example, the classic T-Pose. The user selects the mesh, opens up our tool GUI, and clicks the button to automatically rig the mesh with a few custom paramters. The tool will then automatically create, proportion, and attach a skeleton to the mesh, enabling the user to animate with ease.
At its core, the tool will fit spheres into the volume of the input mesh, and will use a searching algorithm to find the best pathways between these sphere-nodes. The resulting tree becomes the positioning data for the skeleton joints, and is then bound to the mesh.
User can select threshold value and voxel grid size
Threshold = accuracy of edge graph construction
It is the same threshold value described in Pinnochio that affects the cutoff distance during the medial surfaces calculation
Resize to unit cube
Calculating medial surfaces
Distance from each voxel
Edge graph construction
For bipeds in a predictable pose
Arms/legs on the same side, sagittal plane of biped near the center of the unit cube
Create and bind Skeleton
Standard biped hierarchy
Successfully used meshes from Pinnochio’s OBJs to test our tool