A MilBrushMappingMode specifies whether the value of another property MUST be interpreted as absolute local coordinates or as multiples of a bounding box's size.

 typedef  enum
   Absolute = 0x00000000,
   RelativeToBoundingBox = 0x00000001
 } MilBrushMappingMode;

Absolute:  The value MUST be interpreted directly in local space.

RelativeToBoundingBox:  The value MUST be interpreted as a fraction of a bounding box measure.