If anyone is interested in using this for mesh simplification, VTK has a built-in class that implements the quadric error metric called vtkQuadricClustering: https://vtk.org/doc/release/5.0/html/a01938.html/.
If anyone is interested in using this for mesh simplification, VTK has a built-in class that implements the quadric error metric called vtkQuadricClustering: https://vtk.org/doc/release/5.0/html/a01938.html/.