Improve motion blur vector output
Motion blur vector outputs or pixel velocity maps don't work well when using Mental Ray with an animated camera, to the point that a separate plugin (Spotmask) has been created to correct the issue. Also set defaults for any rendering of pixel velocity to match the color information required by the major post-processing tools (RE:Vision Effects in After Effects, etc.). We shouldn't have to buy a separate plugin to fix what is seems like a bug in calculating pixel velocities.
Sorry, I fail to reproduce that. What EXR options are you using?
I suggest you either provide some step-by-step instructions how to get to your results, or you upload a .max file or you directly report this bug at http://www.autodesk.com/3dsmax-DefectSubmission
Mental Ray velocity passes (from G-Buffer or Render Elements) give inconsistent or unusable results, and I believe that this happens when the camera is animated. After being unable to use velocity passes for any significant motion blur, I have incorporated the Spotmask plug-in into my workflow (http://www.spotmask.com/spotmask-new-velocity-pass-added/) and it works exactly as I would like it to, taking into account camera motion in the velocity pass. My current workflow is Mental Ray rendering out EXR images with velocity and object ID channels in the EXR image. Those EXR images are then brought into After Effects and the velocity pass sent to RE:Vision Effects' motion blur plug-in.
Basically, Spotmask has fixed the issue, but this shouldn't likely be an issue.
@rgayan21: Can you provide reproducible steps?
I did a little testing and it seems this problem does not occur if you render to EXR.
I'm also suffering with this
Could you please provide some more information (what 3ds Max version, what render settings), maybe some step-by-step instructions that reproduce your problem?
Sounds like a bug to me?