I’m in big trouble with Vray 1.5 SP3a velocity element and Nuke 5.1.
Here (attachment) are some screen shoot to explain my problem.
Camera is fix and I’ve got “motion blur” on it.
The base plane is fix.
The little plane is rotation.
The torus knot is rotating.
The torus is translating for floor to sky and rotating from center.
The capsule are translating.
But from now i’ve got nothing working…
It’s not really a vray problem, so you can move this thread… but please help !!!
go multi-channel exr, much cleaner…
pm me if you need anything, but it’s just using the layer, rather than shuffling.
There are other nuke users in this forum who might have more of an insight - Thorsten or dimo perhaps are the guy’s to ask though - this is only a quick thing as you can see…
so, I might have mis-understood. - do you mean the .exr’s are slower in nuke from the VrayFramebuffer - if so then you are of course right; being tiled not scanline.
However this is the only way to get a multichannel exr out of max, so just convert them to scanline exr’s afterwards and they will be quicker in nuke. Zip 1 scanline is the fastest.
If you mean to renders take longer to process in the VrayFrame buffer compared to the Max one, then no - they are the same.
I mean Nule is slower with vray’s frame buffer exr.
Vray is not slower with his own framebuffer
So I try with Multilayer EXR, and it work great. So I investigate a little and the multilayer EXR VrayVelocity look like the first attachement (non-moving objects are black), the vrayvelocity element is the second attachment (non-moving objects are middle grey).
So I add a color lookup to my comp to get the non-moving objects black, like in the multilayer EXR and it works. (compo on attachement 3)
Thanks for the help !!! Hope it helps other peoples…
you shouldnt have to do a color lookup. We use VectorBlur quite a lot and it works out of the box, so i am not sure what’s going wrong there.
Edit: Just gave it a quick go. Works like a charm here (see screenie). Let all
settings in max untouched. In Nuke piped it straight into the Vectorblur without any additional nodes and then just selected VRayVelocity, set mode to forward (better quality) and set the alpha in the VectorBlur (to add proper edge handling).
I am very interested to get the motionblur with vectorblur in nuke, too.
but I don’t get the multilayered exr out of max. what’s the exact workflow to get the velocity channel into the exr? In nuke I don’t see the vrayvelocitiy channel. how to test the exr file if all additional channels are saved with the exr?
- Add the VRayVelocity Renderelement
- Turn on VRayVFB
- Select save raw image
- Enter filename.exr (instead of vrimg, wich is not offered in the dialogue. Just type it in)
- Done
As you can see in your test, the pixels are blurring but the blur does not exceed to an object to another or out of alpha.
For now the problem can not be resolved if you use Vray or Scanline render because they can not render a correct Velocity pass as Maya, compatible with existing software and plugins: Reelsmart VectorMB and SmoothKit, Nuke and Fusion …
These plugins require the direction of pixels moving in Red and Green channels and speed of moving of each pixel in blue channel, while Vray renders nothing in blue channel or he can put the useless Z displacement .
i dunno for fusion or reelsmart…but this is not expected in nuke and it works flawlessly out of the box. And it sounds like a waste of calc and space tbh as a vector contains speed (via length unless normalised).
Well, you get the magnitude of the velocity from the red/green channels already; if necessary, you can calculate the blue value from them. But in any case, as Thorsten and jacksc02 mentioned, things work fine with what you have now.
So, I propose a game : Try to make a correct motion-blur with this image and his velocity pass and return it.
I provided you a V-Ray test render with his Velocity-pass and you try Motion-blur with your software or plugin to see who works with this kind of velocity pass.
The Image :
Thez Velocity pass :
you can download the 16bits png here (right click) - Max Velocity = 15000
) but do you get the same result with “ignore Z direction” unchecked?
Why would the VrayFrame buffer be slower? Man, I just can’t use the Max frame buffer anymore… 
