I really have to make a tutorial for that, it's been asked before. It takes a lot of messing around with, but what it is a bunch of lattices. Make a lattice, and edit it. Make it black, and then add some spikes. Add a gaussian blur so the corners round out, then clip it so that all you get is the spikes in a circle. Apply the Misty Afternoon cloud texture to it. It should look to thin. Then, dupe it, (I did it on a path so its easier to move later), and rotate and scale it slightly to give it some volume and to give the illusion that it's not a duplicate. You'll need to play with how many duplicates you make -- to many, and it'll be too thick, too few, and it's too thin. Then, dupe it again, this time, change it's Material to a water so that there's some actual water in the foam. Once you've got a splash, you'll need to rotate it so that it impacts properly, and so that it looks right. I have about 12 lattices in that image, and I might add some more to the bottom of the image. Just know that it adds a lot to render time, and I crashed Bryce many times working on it. It may be a good idea to make a separate file for the wave and save it frequently. You can merge the wave file into your scene later. (I noticed I was crashing when I had a lattice or two or three on the clipboard, so copy/paste was risky on my Mac (180MB RAM dedicated to Bryce). I hope that helps. I'll post a proper tutorial one of these days, I'm just too busy at the moment. It's a tedious process that takes a lot of trial and error, but it's workable. I'm currently working on a way to create that effect (and others) with the Tree Lab. All I have to do is figure out a way to edit the leaf shapes, and it'll be a piece of cake. Anyone know how to add custom leaves to the TreeLab?