A method for generating a facial blendshape rig from a source rig and a set of corresponding example poses. The method alternates between optimizing for the blendshapes, utilizing an approach derived from Deformation Transfer, and for the blending weights. The resulting blendshapes carry the source's controller semantics and maintain the identity of the target.

Implemented in C++17

Using:

• Eigen 3
• OpenMesh
• CXXOpts

Download and install Eigen, OpenMesh, and CXXOpts according to their documentation.

Adjustments to CMakeLists.txt may be necessary depending on your environment. Lines marked with "<<<" are likely candidates.

To prepare the build environment, create a build directory and run cmake inside of it.

mkdir build
cd build
cmake ..

To build the Example-Based Facial Rigging, make the 'ebfr' target.

make ebfr

ebfr --source-blendshapes "../data/source/blendshapes" --source-poses "../data/source/poses/" --source-weights "../data/source/poses/weights.csv" --target-neutral "../data/target/blendshapes/neutral.obj" --target-poses "../data/target/poses/" --target-weights "../data/target/poses/weights.csv" --output "output"

• --source-blendshapes: Path to the directory containing the source blendshape mesh files
  • Blendshapes are expected to be named sequentially from '0' and in OBJ format
• --source-poses: Path to the directory containing the source pose mesh files
  • Pose mesh names are expected to match the names found in the weights file
• --source-weights: Path to the source pose-weights file
  • See Weights CSV below
• --target-neutral: Path to the target neutral mesh file
  • Neutral mesh is expected to be an OBJ file
• --target-poses: Path to the directory containing the target pose mesh files
  • Pose mesh names are expected to match the names found in the weights file
• --target-weights: Path to the target (estimated) pose-weights file
  • See Weights CSV below
• --output Path to a directory to write the final target blendshapes

Header Row

Pose, 0, 1, ..., # of blendshapes

Row

PoseName, w0, w1, ..., wN

PoseName should match the name of a mesh in the corresponding poses directory

#####Example

• There must be a one-to-one correspondence between source and target meshes.
• The source and target poses must also correspond to one another.
• All meshes are, at this time, expected to be in OBJ format
• Runtime on a reasonable PC is roughly 50s with 13k vertices, 28 blendshapes, and 10 example poses.

Deformation Transfer for Triangle Meshes by Sumner, Popovic. 2004 (Project)

Deformation Transfer for Detail-Preserving Surface Editing by Botsch, Sumner, Pauly, and Gross. 2006