When you say your FileTransform results differ from Nuke's, is this from using a Vectorfield node, or an OCIO FileTransform node, or perhaps an OCIO Display node entirely? Also what format of LUT are you using?
(I'd also recommend using INTERP_TETRAHEDRAL where possible)
Actually, what we found was creating an actual OCIO config out of the LUT file transform produced the proper results. Not entirely sure what the actual difference is under the cover.
