Origin
Specifies whether the blend shape is relative to the base object shape’s position, rotation, and scale, or is directly specified by you.
Blends the base object shape to the target object shape(s), taking into account any differences in position, rotation, and scale between the target object shape(s).
Specifies that two special attributes, baseOrigin and targetOrigin, provide origin information. For more information on these attributes, see the online Node and Attribute Reference and the MEL Command reference. You can use the setAttr MEL command to set the values of the baseOrigin and targetOrigin attributes.