I've been working on an underwater scene in Superfly, P11, and using this method for caustics and godrays, but I'm having trouble fine-tuning the caustic ratio. For a while I couldn't get it to work at all and then just on a whim I plugged the math node used to invert the image directly into the transparency and suddenly I could see the caustics. For some reason, that Add box messes me up, and I've tried every adjustment from .097 (very blown out, ouch) to .99999 (nearly black). All it does is adjust my overall light level but the moment I plug that box in, caustics go away entirely. I even tried changing my measurement interface and that did not seem to make much difference. I'm wondering if the scale of the scene isn't what's affecting things somehow. I have no environment sphere in place, since it didn't look like one was used in the example above. Infinite light at 1500%, 1% size, shadow blur at .5 which produces a rather fuzzy caustic--.2 produces a much sharper one but then I'm back to square one with trying to modulate the caustic ratio. I have my gobo plane just above the frame of my render, as low as I could put it, practically on top of my shadow box. What am I missing?