Vray Velocity - correct settings for Nuke and Frame Edges

[chronopsis]

Working on compositing a simple motion blur test in Nuke, rendered in Vray with a velocity pass. The issue I'm running into is with frame edges - objects crossing the edge can lose their imagery. Normalizing the vector blur node in Nuke 'fixes' this, but wrecks the rest of the alpha edge. Anyone solve anything like this with Vray settings? Or is this a Nuke-only problem?

non-normalized (correct alpha on rest of object, blank edge on left side)


normalized (ruins rest of alpha on right side)

[Morbid Angel]

You have to consider that motion blur in real 3d render would sample the objects outside the frame as well so in 3d motion blur you would have correct edges along the frame border. However since this is a 2d blur (*cheat) the same logic applies, however there are no 3d objects or data outside the frame. To solve this you must render with a little bit of overscan, maye 5% or more depending on how strong the motion blur is in your scene. This will have the data needed outside the frame to produce blur along the edge.