When you insert a drawing created with drawing units which differ from that of the current drawing (i.e. Insert an Architectural Imperial dwg which uses inches, into a Civil drawing which uses feet) and Insunits have been properly set, the drawing is automatically scaled to be in the target drawing units. The (XYZ)EffectiveScale value will normally be 1 whereas the (XYZ)ScaleValue would be the actual value needed to obtain the conversion (0.083333 in the case of the inches to feet scenario).
; XEffectiveScaleFactor = 1.0
; XScaleFactor = 0.0833333
; YEffectiveScaleFactor = 1.0
; YScaleFactor = 0.0833333
; ZEffectiveScaleFactor = 1.0
; ZScaleFactor = 0.0833333
T
