  Direct Delta Mush is a novel skinning deformation technique introduced by Le
and Lewis (2019). It generalizes the iterative Delta Mush algorithm of
Mancewicz et al (2014), providing a direct solution with improved efficiency
and control. Compared to Linear Blend Skinning, Direct Delta Mush offers better
quality of deformations and ease of authoring at comparable performance.
However, Direct Delta Mush does not handle non-rigid joint transformations
correctly which limits its application for most production environments. This
paper presents an extension to Direct Delta Mush that integrates the non-rigid
part of joint transformations into the algorithm. In addition, the paper also
describes practical considerations for computing the orthogonal component of
the transformation and stability issues observed during the implementation and
testing.
