Vrayvelocity --- can't 0 velocity be invisible?

[davision]

Okay, I'm starting to get the hang of this velocity vector stuff. However, I don't understand why a stationary object generates a visible velocity channel.

If I have a stationary camera and an object moving in front of a stationary plane, the plane generates a grey velocity channel, while the moving object gets colored appropriately. When taking the motion vector image into AE for use with Reelsmart motion blur, the grey plane "vectors" cause problems with the moving objects motion blur and it only blurs within it's own boundaries -- it will not create a true streaking effect. If non-moving objects were invisible to the vrayvelocity then it would work great.

Optionally, I could do a separate pass with only moving objects and hide all non-moving objects. That is possible -- but if I have a sequence where a camera is initially stationary (so background is non-moving) but then the camera moves (everything is moving) the separate pass idea won't work (unless I create a pass for the moving frames of the camera separate from the non moving frames) -- which is a pain.

It really seems like stationary objects should be hidden automatically on the velocity channel.

[instinct]

am just wildly guessing. is it exactly 50% grey ? Cause then i´d assume the vector for motion on x ranges from 0-1 where 0.5 is the center and <0.5 means moving to the left and >0.5 means moving to the right. As said am just guessing here

Thorsten

[davision]

Yes, it's middle grey 128,128,128 (or the 16-bit equivalent).

But it would seem like it would integrate much better with RMSB if it were alpha 0 whenever it was 50% grey.

I'm toying with an a way to key out the middle grey in AE, but it's a little messier than it needs to be.

[instinct]

ic, well as velocity is a renderelement it doesnt have an alpha currently. no idea if that will change.

Thorsten

[Da_elf]

i was told earlier by morbid that vrays velocity is geared towards nuke and MR is better for combustion and RSMB. apparently the colors are different or something

[davision]

i was told earlier by morbid that vrays velocity is geared towards nuke and MR is better for combustion and RSMB

I really hope that's not true. I'm sure Nuke is an incredible application -- but I'm fairly certain it's quite expensive (never seen the price) and I'm also fairly certain it's only a tiny fraction of the compositing market -- or at least where vray users are concerned. Ask people how many people are using Combustion or AE vs. Nuke and the numbers are probably 50 to 1 (at least).