Wave spreading application

Hi,

I request some details on the wave spreading computation in the fatigue FTOPT2 card.

If I define a single heading wave (probability of occurrence 1.0 or 100%) at say 0 degrees and also specify a wave spreading, is the wave energy distributed from 270 degrees to 90 degrees as per the defined wave spreading? I would appreciate a write up/calc. note illustrating the application of wave spreading for such a wave definition that is coded in SACS. I could not find information in the SACS manual to answer this question.

Thanks and Regards

Sanjay