Motion blur using a velocity pass
Vray

  1. Create velocity render element
  2. Uncheck "clamp"
Nuke

  1. Pipe the velocity pass into a grade with these settings:
    • Black point: 0.5 (this is to remove the grey background)
    • Black clamp: off (since motion vector contains both positive and negative data)

  2. Using copy node, copy the R and G channels from the velocity pass to the forward u and forward v of the rgb beauty
  3. pipe this into a vectorBlur node with these settings:
    • uv channels: forward
    • multiply: 0.5 (this equals 180 deg of the shutter)
    • method: forward
    • check use rgba.alpha (The alpha is necessary for the proper edging of the motion blur)
  4. The resulting node graph should look like this:

All content © copyright Light Collab.