Hi TM, Particles only exist as a Hot Point, not an actual mesh. They are really non-dimensional. So, no, you can't make them accumulate. The Metaballs option can fake fluids until you start dealing with issues of accumulation. Blender is free and has a pretty good fluid solver/generator if you want to give it a try. www.blender.org - for the program. They've got some good tutorials on the site. Also, for additional Blender info, this site is good - http://www.blenderunderground.com/ Blender's interface is, um, unique. Takes awhile to get your head around - at least it did for me - but a cool program. I have brought fluids via sequential .obj export into Carrara from Blender but it takes awhile to make them look decent because it's a frame-by-frame adjustment process in the Vertex modeler. Blender has a decent renderer but it doesn't let you work with the other Carrara capabilities you've come to know and love. ;-)