I’m posting little, free script to add and control foam on custom wave object (for eg. imported from dreamscape).
This little script will get verticies out of custom object over given Y value, get their velocity and add Particles in that position. I’m using Null object to better visualize Y threshold value.
I have also added random function for little variation when adding particles.

—- UPDATE!!!

–> [GET A SCRIPT FROM RF SCRIPT PAGE]

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# Name : CustomOceanSpray
# Icon : Spray_icon.png
# Toolbar : Yes
# Author : Albert ‘tmdag’ Szostkiewcz
# Website : http://tmdag.com
# Date : 30 July 2009
# Version: 1.2

Kind : Batch script, Event Script

Why?:
You can choose custom, animated ocean object (for eg. imported from Dreamscape)

Installation:
1. Copy script file (.rfs) wherever You want
2. Open Realflow with Your scene file
3. Open menu scripts / Add
4. In Add Script window, Name field enter “CustomOceanSpray”
5. Choose Spray_Batch.rfs in script field
6. Choose Spray_icon.png for Icon
7. Press “New Folder” (bottom left) and create folder for scripts
8. Choose created Folder and press OK
9. Open Even Script (Layout/EventScript of press F11), paste(replace) text from Spray_event.rtf

Usage:
Choose Your desired custom ocean object, fire up CustomOceanSpray Batch script (from toolbar):

Spray Type = Dumb
You can choose what kind of spray type You want to create (Dumb type is usually enough)

Spray rand in m = 2
Spray randomisation in meters (it depends on Your scene scale so You may want to increase or decrease it)

You may want to add daemons like Gravity, k_age, k_Volume, Noise_field, wind etc.

SCENE SCALE!!
Scene scale is very important in setting up ‘rand in m’ value!!!!

FAQ:
Q: I get half of my ocean object covered with particles! what should I do?
A: Check Your Axis setup (Realflow / Preferences), Y should be Upwards

Q: My particles are flying around!
A: Check If Gravity force is connected and try lowering ‘rand in m’ value because it depends on Your scene scale

Pros and cons:
It’s quite quick! but number of points depends on number of object vertex (I’ll try to change that soon)

History:
30.07.2009
- First release

sea

[Sample mpg]

Nice example from Alex:
preview00057
and another example HERE

Here is one interesting plugin, deformer and tutorial, how to create choppy waves in Maya [HERE]
Personally I haven’t tested it so please give some feedback, I could improve my script for Your better workflow :)
wave wave