Steam over swimming pool

Anyone have any good techniques for creating some decent looking steam over a swimming pool - even if I render it seperately and comp it in?

OK - I seem to be able to get a volume fog effect looking quite good using a box gizmo, but the fog itself quite hevily illuminates the scene. How do I stop the fog generating GI? Its not selectable in Vray Properties.

Just assign a Vray Material Wrapper to it first, and the actual fog material as a sub material. That will let you have control over it’s GI emmission/reception.

if your using the gizmo in conjunction with an atmospheric effect you cant stop atmospheric effects from contributing to your scene. so your best solution is to render your scene without the fog. then render the fog on a seperate pass to comp over the pool