What is difference b/w (professional)3d website and flash websites (please read details b4 answer)?

I want to develop a professional 3d website as my BS-Software final year project for A SMALL STORE or SHOP ..in which all the actions are performed as a real world, all the webpage is similar to the shop infrastructure where user/Customer go to shelfs by moving freely in the shop and chose the items by analyzing items ALL IS DONE IN A 3D realization of shop by the costumer ALSO [[[ PLEASE GIVE Suggestion IF ANY regarding THE 3d WEB DEVELOPMENT ]]]]