Can Houdini generate motion vector pass for Volumes using raytrace Engine? If Yes, Please share how and How can we optimise it for faster rendering.
I have tried using micropolygon but it is very slow.

Bring up the Houdini Help browser and type Motion Vector in the search field. There is an example file you can review.

May be I miss something but I am looking for motion vector pass for fluids/volume using raytrace engine,Hope there is also an example file for it which I can review and understand.