Hasta La Motion!

Hi all, I’m a little new to Nuke so I may have overlooked this in the manual or missed a forum post but I’ve looked everywhere and I can’t find the answer. I’ve made up a 3D set with lights, animated cameras and a readgeo. Now due to the way certain things in Nuke work I’ve had to make sure that the whole set is placed in positive space, which I thought I did. However it turns out that some of the set is running into negative space and since I’ve duplicated my basic setup a number of times (Different angles e.t.c) and have a lot of keyed cameras (and lights in specific places relative to the read geometry) is there any way I could reposition the world zero point to put everything back into positive space? Or is this a classic gotcha?