Erlik,

Actually, I do wish to add caustic reflections to the wall of the pipe above the water as well. I'm also thinking about adding some caustic effects to all the other water sources in the image. So, your advice is helpful in both regards. Thanks.

I'm using Caustics Generator v1.3 to create the caustic gel pattern and editting it in Photoshop. (http://www.lysator.liu.se/~kand/caustics/).

Placing the caustics gel on a scaled up cube light above the scene, with cast shadows turned off on the light, seems to be working quite well. It is not only creating the caustics bellow the water, but also the caustics on the walls of the pipe, which could be viewed as the reflections off the water. I'll post an image later today with the caustics added.

The product, storm drain pipes, curb, pavement, and flat planes that represent the cut-away dirt were all modeled in Rhino. Everthing else was done in Bryce. All the details and stones added to the dirt were accomplished with terrains and a few stone objects. The grass is also done with terrains.

Floating Oil... Do you mean the oil stains on the pavement. (There isn't any other oil in the image) If you think there is, please let me know. Darn, I was hoping that the floating effect wasn't too noticable. :) The only way I could think to quickly create the oil stains was to copy and past the pavement three times and raise each copy by 0.01 Bryce units. A different transparent oil stain material was then applied to each copy of the pavement. Unfortunately this tended to make the oil look like it was floating. I think the .jpg compression might also have enhanced the floating look.

 
GROINGRINDER,  
 
Thanks for the compliment. :)