Originally Posted by andy gee
In regards to your render layers.
What I have done is for each layer if I have elements in the layer which I want the particles ie bubbles to interact with I applied them to the layer then simply added a matt black texture to them in that layer that way you get the interaction and then because its black, your compositer will read it as being cut out still leaving your other stuff in tact.
Hey Andy, sorry for the late reply...i've been so busy lately...
I added the default black Surface Shader from the Maya nodes in the Hypershader to the anchor, leaving the sand particles as is and rendered it out as a .tga. I brought it into after effects and shake to see if I could get the anchor matte to dissappear. I didn't have much luck, as the alpha channel still showed the anchor as white. In both softwares I used a Channel Reorder to try and put the alpha into one of the colours, say Red for eg. which works to get rid of the black matte anchor shape YAY, but it also takes away the red from the image. Have I missed something?
P.s. your rays look much better than mine...I might have to try your technique.