I had a line that shows a flow of energy and in the first composition it flowed right to left. i then precomposed that and brought it into another new composition and once it was in the new comp the flow was reversed - why would this happen - i didn't change any off the parameters of the original composition that contained the vegas effect - what do i need to do to lock down the direction
Using the active camera for preview even with 3-D layers I cannot reproduce your problem. If AE is up to date and you cannot discover the problem by carefully checking the modified properties of the layers, we need lots of details about your workflow and your composition.
As Rick already said, without knowing your exact settings and project structure nobody can tell you much.