Vray Velocity pass with Fusion 7.5?

[3Dmotif]

how do I use the velocity RE with Fusion 7.5's Velocity blur?

Velocity RE was rendered out of the VRFM 3.0 beta while back but trying out comping in the new Fusion 7.5.

[Svetlozar Draganov]

Use VectorMotionBlur node with X Channel set to Red and Y Channel set to Green:

Sample Scene/Comp=>http://ftp.chaosgroup.com/support/95...ector_blur.zip

[3Dmotif]

yeah I did that.

Ok I tried that but ended up with no motion.

After reading else where I found that I needed to add a BC node between the vectors and the the vector blur. with the Brightness set to -.5.

then I had to set the scale of the vector blur to double the the value of what the motion value of the Velocity RE was rendered at to get it to look right.

if I try it without the BC node on the vectors I get the whole scene blured

[Svetlozar Draganov]

Thanks for the feedback.

[Morbid Angel]

this is because if you look at the vector as svetlozar has it, its not a pure color since vray renders it against grey. So you must compensate by removing the grey value and extract the pure color - then it will be correct. Also if you use multichannel exr, it should just work right away.