can we do engineering after B.sc or M.sc?
Yes you can definitely do Engineering or perhaps get an Engineering degree after B.Sc. or M.Sc.
In case you are B.Sc., you can pursue a Lateral B.Tech degree from some of the Leading Universties or you get acquire an Associate Degree in Engineering (Equivalent to B.Tech) from Institutions like Indian Institute of Metals or Institution of Engineers.
In case you are M.Sc., I believe qualifying GATE in respective Engineering Subject of Interest, followed by pursuing Postgraduation/M.Tech from some of the higher technical institutes like Top IITs, NITs, BITS Pilani, IISc Bangalore and so on. Most of the above institutes as well as Other Leading Private Universities have liberalised their Admission Policies and have accept Science Postgraduates in M.Tech, respect to performance in GATE and Interview.