can ofdm transmitter be simulated with fft

http://www.complextoreal.com/tutorial.htm

in this tutorial they say that in ofdm transmitter fft can be used in place of ifft and ifft in place of fft
is it true?
or fft transmitter must have ifft?
if fft is used in transmitter will there be mapper? bz it only converting input bit sequence in to complex (frequency) constellation