This MCG object let you combine multiple object as one mesh while keeping animated transformation and deformation.
You have two methods to choose the object to combine. I’ll call it, Source Objects.
The first method is selecting Source Obj Tree Root. If you choose an object, all descendant of selected objects will be used as source objects. You can have non-mesh object in the hierarchy. The MCG will filter out non mesh automatically.
!!! This methods doesn’t support deforming mesh !!!
The second method is manually selecting objects by Add Item/Remove Selected button.
You can use both methods at the same time. Any object chose by either methods will be used.
Another feature of this MCG is that you can define local space origin and orientation with Local Space Ref.Obj. What? I know it sounds confusing. Let me explain.
If you don’t choose any object as Local Space Ref.Obj, the position of this MCG object becomes the world origin for combined object, and the orientation of this MCG object will defined the world axis of combined object. Therefore, If you make this MCG object at world origin without any orientation, the combined object will be exactly overlapped with source objects. If you transform this MCG object, the combined object will be offset as much as this MCG transform.
But, if you choose an object as Local Space Ref.Obj, the transform of the object will defined the origin position and axis orientation. In the vimeo video, you can see what happens if you choose the point helper which is projected from Bip001 object to ground as Local Space Ref.Obj, The combined mesh animation is happening around the helper object.
The last option is Use Src Obj Tree Rool. If you check this checkbox, the object which is used for Source Obj Tree Root will be used as Local Space Ref.Obj, too.