question about render elements: normal

[imagecube]

just switch from MentalRay to Vray. everything works great so far.
I noticed the normal render element from Vray is different from the render pass from MR.
It looks similar to the normalCam from MR but x is inverted. Y and Z are close but not exactly.
We have used the normal passes(camera, world and object) in re-light in post quite a lot. just want to make sure the normal in the render element from vray is suitable to use in re-light. if not, should I connect the info from sample info to extra-tex to get a more accurate normal pass. Thanks.

btw, figured out how to output position pass from vray

[Svetlozar Draganov]

For 2.5 re-lighting it would be better to use VrayExtraTex render element with plugged Sample Info node - it will give you the same result as the one you got from MR.

[imagecube]

Thanks for the the certification Svetlozar. Now we can get the necessary render elements to use in 2.5d relight.
but I am still not sure when and how I should use the RE:normal from vray directly. I also notice the background has some value in RE:normal even there is no geometry.

[vlado]

but I am still not sure when and how I should use the RE:normal from vray directly. I also notice the background has some value in RE:normal even there is no geometry.

The element was mostly designed to be used for baking normal maps.

Best regards,
Vlado