FBXImportConvertDeformingNullsToJoint -v [true|false];
FBXImportConvertDeformingNullsToJoint -q;
Converts deforming elements into Maya joints.
True
Transforms all deforming elements into joint nodes.
Note
This option was originally provided because Maya did not support locator elements (that is, transform nodes that are not joints,)
within a bone hierarchy. While Maya now supports this, in some cases this option improves the skinning behavior.
See Deforming elements to joints for more information.