OverMorpher PoseSpace is a 3Dsmax plugin dedicated to Pose Space Deformation.
It is pretty similar to the SkinMorph, Corrective poses driven by your Rig.
Except the poses interpolation is more reliable. The SkinMorph modifier drives the poses depending on the angle between 2 bones.
And because of the nature of rotations in 3d softwares and rotation orders, in some cases, the interpolation doesn’t work as expected.
Mainly on bones which have more than 1 free angle.
This plugin is based on what is called a Radial Basis Function, and in this case it is a bit simplified.
So it doesn’t use angles between poses, but distance between two points, which solves the angle problem, and open new possibilities.