bagginsbill
I guess what I'm trying to say is if I render a picture and then I want to add the water to it, I can only pose the characters one way, because if I move them around and then try to put the water into the scene, I can't change the angle to match the picture.  If you notice in the above picture, the waves can only be in that angle (Horizontially).  For example I want to make a picture that pans towords the water more as opposed to be horizontial.  I can't change the angle such as moving it left to right or up and down.  I hope that makes sense. 
Adrian