UV pass will allow you to re-texture surfaces and add some elements ( like text, batches, picture frame ) later in the compositing stage. Here i place my name on the surface and apply motion blur inside nuke.
Creating UV pass inside MAYA:
Open up render settings under Passes tab select create render passes and choose UVpass and add.
If you want to create custom UV pass Follow below link.
Enable float values for rendering
For render UV pass from MAYA you must change your colour bit depth from the standard RGBA 4x8Bits per channel to RGBA (Float) 4x32 Bit (full float).
Open up your 'Render Settings' and at the bottom of the 'Quality' tab change the 'Date Type' to 'RGBA (Float) 4x32 Bit.
choosing File format for rendering from MAYA
UV passes contain infinite values so you can't store UV passes on clamped image formates, such as .jpg, .tga etc. So we need to use image format like .exr which can store float values.
Render your images as .exr sequances from MAYA.
stMap tool in NUKE:
stMap node use UV pass information for re-project your texture on your surface inside Nuke. Also you can place what ever you want on your surface.
Here i add my name on top of my object using UV pass and apply motionBlur using "vectorBlur".
For working with "2D motion vector" inside NUKE follow below link:
stMap-> your UV pass
src-> your custom object (my case Text)
Dealing with stMap:
On stMap node set UV channel none to your custom UV channel and color channel all to rgba.
Applying Motion Blur:
for more information dealing with vector blur:
Motion blur applied result.
Hope this page help you.
software used: Maya 2012, Nuke 6.3v6.
UV pass: https://skydrive.live.com/redir.aspx?cid=776f8351d9892b6a&resid=776F8351D9892B6A!252&parid=776F8351D9892B6A!133
Nuke comp file: https://skydrive.live.com/redir.aspx?cid=776f8351d9892b6a&resid=776F8351D9892B6A!253&parid=776F8351D9892B6A!133