VRay to NUKE motion blur workflow

Here we create a teapot moving from left to right and right to left, move up and down, move backward and forward. In 3ds max, with V-Ray renderer, generate a color map represent 2D directional (vector) information, which we can use it in NUKE for motion blur effect.

In 3ds max 2011:

1. Add VRayVelocity element

2. uncheck "clamp velocity" and "ignore z direction. Render one single frame  to see the value of "max velocity in last frame, this will give the what is the max velocity of your animation. In this example it is 60. So we fill in "max velocity with 60.

3. Check "Enable Build-in Frame buffer, save files as EXR files

In NUKE 6.3:

4. After read in our EXR sequence files, let's go to Viewer/VRayVelocity to check if  the VRayVelocity is generate correctly. When object stand still, there should no color, when object moving from left to right, the color should be red; 

When moving upward shows in green color.

5. Add a VectorBlur node

6. Change your "uv channels" to VRayVelocity, offset to 0, method to "forward. We are done!

7.  Motion Blur correctly apply to our moving object.