I have generated a directional wave spectrum consisting of a swell component and a wind sea component, the two being 90 degrees apart.

I have 2 wave genration lines forming a 90degree angle.

Using the Mike21 toolbox, I'm generating random waves using my user defined directional spectrum.

However the toolbox still requires a Main Wave direction and maximum deviation from main direction. This confuses me slightly because my directional spectrum already contains the directional component.

For now, I have used the average wave direction as the main wave direction (i.e. 45 degrees between the swell and wind sea) and specified the max deviation as 45 degrees.

Results look believable but can someone put my mind at ease if this has been the right approach?

thanks and regards