[ns] how simulate obstacles!!!

hi everyone, some knows how can i simulate obstacles like buildings trees ans so on.. thanks

[ns] how simulate video?

hi, im interested to make simulations of the behaviour of real time services over ad hoc, so i want to know how can i simulates video traffic sources? thanks in advance...

[ns] vanet's simulation

hi, i would like to know, how can i simulate vehicular networks using ns2? movement models, obstacles and so on i need to simulata a urban scenario. thanks