Is fat transferred to hips during bbl or it is actually a Fat injection to buttock that gives illusion of hips?

Depending on the anatomy before surgery, autologous fat can be transferred to either the buttocks or the lateral thighs to achieve the look that you desire. This is typically a combination procedure performed in one setting. 

  In my practice, both are done depending upon patient desires.  The buttocks can be filled laterally and the hip areas can be filled as well.Kenneth Hughes, MDLos Angeles, CA

Most of the fat is transferred to the buttocks proper, rather than the actual lateral thigh or hip region.  The lateral buttock is obviously continuous with the hip region so you get improved contour of the lateral thigh.  The lateral thigh or hip can be injected but because the skin is tightly adherent to the muscle you cannot get much augmentation.   Thank you for your question.  Best wishes.