Point Position and Object Normal in Maya mental ray

Point Position (Point World):

create 3d point clouds from Maya and view it in Nuke 3d space!
Create a render layer ex: pointSpaceR
base on what kind of point space you need: pointCamera / pointObj or pointWorld (mostly this one)> Surface Shader's outColor

one thing about use linear workflow in maya mental ray, camera's mia_exposure_simple node must be remove/ break connection.

This point position render can be apply in Nuke's PositionToPoints node, xyz input for this point space render/ col input for normal color render.

Base on D.T. training said, point space render suggest openEXR format and no anti-Alias render feature turn on!

first: in the pointSpaceR render layer in render setting> Passes> Create a new "Beauty" passes from maya render passes library> Add to associated passes
second: double click the beauty and dis-check "Filtering" and set Frame Buffer Type "32-bit Float", of course you also need to enable "RGBA (Float) 4x32 Bit" under Quality/ Framebuffer in render setting.

object Normal:
object normal pass can be render with point space pass together, simple add a default pass call "Object Normal (World space)" from library. this also suggest turn off anti-alias on render.
This just the object normal only, no texture normal. If you need texture normal as well, just use colorR render layer that already has well texture bump and displace map setup to add the same "Object Normal (World space)", will get the object normal and texture normal together.