I appreciate the very thorough reply!

However, still a couple of issues.

1) when i create the samplerInfo node, when I click on it in the expression editor, there are no Attributes (when i click on a cube i created i have the whole list of attributes). However, when i run 'listAttr davidSampler' all of the attributes I expect are returned.

2) As I understand it, the 'pointWorld' property actual takes on thousands of values (one for each pixel in the frame) every frame... hence I'm not sure it makes sense to grab the values once per frame... and since that is the case I have NO idea how to proceed lol.

Any more pointers would be great!

Thanks,

David