TAD is a design software that grew from a small time architect's office in Navi Mumbai, India. It arose from deep love and concern for architecture
It is an effort of 30+ years using theories from architecture itself; instead of borrowed work
TAD address the needs of the ordinary architect and simple clients all over the world -- but especially in developing countries.
Keep aside previous knowhow on Autocad, etc. You really can learn TAD within a day