You can use the Scale constraint to transfer the scaling from one or more objects to another. 
         
         To scale a constrained object:
         
         
            - Select a Scale constraint from the Asset browser’s Constraints folder and drag it into the Viewer window. 
                  - If you drag it into an empty area of the Viewer window, the Scale constraint template appears in the Constraint settings.
                     
                  
 
                  - If you drag the constraint on top of an object, a context menu appears asking if you want to assign the object as the constraint’s
                     Source (parent) or Constrained (child) objects .  
                  
 
               
 
             
            - Assign the object that you want affected by the scaling to the Constrained Object cell. 
 
            - Assign the object that you are using to create the scaling effect to the Source 1 cell. 
               
NoteYou can have more than one object provide the scaling information to the constrained object by assigning new objects to the
                     resulting Source cells. 
                  
                 
             
            - Adjust the size of the Constrained object, if necessary, with the Scale fields. 
               
NoteDisable the Lock option to activate the Scale settings. 
                  
                 
             
            - Click Lock in the Constraint settings to lock the position of the objects to be constrained and click Snap. 
 
            - Click Active to activate the constraint. 
 
            - Deactivate the Affect XYZ options in the Properties window Scale constraint settings to disable the scaling effect per axis.
               
            
 
            - Weight the effect of the individual Source objects, if necessary, with the Sale constraint’s Source Weight slider(s). 
 
            - Select either Geometric or Average as the Blend Method from the Properties window Blend Method menu. 
 
         
         
         
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