Marko Vukovic with what he calls a QuickE tutorial showing how to create a relight tool in NUKE using EXR Images to encode both positive and negative values for normals. Checkout the relight tool for NUKE as a download here.
Marko Vukovic writes: “Relight a color pass in nuke by using a normals pass and point position pass generated from any 3D package. I’m using EXR images to encode both positive and negative values for normals and point positions, so make sure when you render from any 3D package to use 32 bit or floating point data. The color pass is simply a constant shader with a texture map applied.”