Problem with VrayVelocity 1.5Sp3a + Nuke 5.1

[instinct]

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).

Regards,
Thorsten

[jacksc02]

The Velocity render element generated by VRay works perfectly in RSMB for Fusion.

[vlado]

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 .

Watch this video to better understand, at the 3/4 of the end it's explain :
http://www.cgarena.com/freestuff/tut...e/pigeon8.html

>> Vlado : It would be a really good thing to add in Vray.

Best regards

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.

Best regards,
Vlado

[noel_d3]

"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

[sv]

could you also share the max file?
In this case though the glossy refractions are going to cause a slight issue anyway

[muoto]

Found this in vfxtalk.com


Use the "multiply" node. It is not in the menu, just go to others and >"update all plugins", then go to the letter M and select "Multiply", now select you VRayVelocity pass and deselect x and z and type -1.

Voila now you have applied a -1 to the Y. and Made the vectors go to the correct side.

Hope it helps

[noel_d3]

could you also share the max file?

Sorry but that is not part of rules of the game.
Do not worry about refraction and try to post an image with motion blur using V-Ray Velocity pass.

> muoto :
Your motion blur is not correct because some objects don't move and in your attached image all is motion blurred.

[instinct]

post an image of what is moving how then. troubleshooting without a target is not a game at all...rest assured it does work as we are using it daily in many of our productions.

[sv]

post an image of what is moving how then. troubleshooting without a target is not a game at all...rest assured it does work as we are using it daily in many of our productions.

this is why I asked for the Max file so I could re-render the Velocity pass - what you have shown looks strange to me. And I would never split channels out but embed everything into an EXR that I know works perfectly from Vray and in Nuke.

I have been using VectorBlur all morning here with this workflow to add MB to renders....

[instinct]

Looking at the image itself reveals that according to this velo channel everything IS moving. Do you have a moving camera etc etc.

As said troubleshooting doesnt make sence before knowing what should happen.

[muoto]

post a reel motion blur rendering from vray, so we can see what's happening

[noel_d3]

Ok guys, it's just what I wanted to hear for Vlado :
The V-Ray Velocity Pass in Render Elements is not usable, it doesn't work for any software.

That's why I don't give the max scene, to be sure you are not using another technique.
I have understood the contrivance of sv speaking of refraction.

For the moment, in the best cases you can have this :
with Reelsmart Motion Blur Vectors and V-Ray Render Elements Velocity pass



It may be noted that the motion blur is no more correct when objects are before another like in front of green plane but it's work if there is nothing in the background, here where it's gray.


It confirms that this Render Element pass should be amended so that we can add the speed of pixels in the blue channel, for having a valid Render Element Velocity pass like it's explain at the end of this video :
http://www.cgarena.info/files/pigeon...odcast-019.flv

[instinct]

It IS usable. It may not work in any software. But it is working fine in many apps.
Using special tricks ? Such as getting the settings right in regards to the App used ? :P

Posting the Scene might help to investigate on the issues you are experiencing. And keep in mind since it DOES work for many ppl simply changing it might break it for these ppl.

Regards,
Thorsten

[instinct]

On a quick note i get the impression you offsetted the speeds by tweaking the min/max parameters. Things that are supposed to be still have a value of 0.241

Subtracing that value from the velocity channel gets pretty close to what you posted. So i would guess it is a settings problem eventually.

Regards,
Thorsten

[sv]

yes, I have to agree with Thorsten here.
The Velocity channel you posted shows values (so movement) on all the objects - load the velocity channel into a post app, read the values over the black clip thing - they show movement...
This is why I asked for the scene, because I wanted to be sure that the Velocity channel was being saved and stored correctly.
MultiChannel EXR through the VFB is a sure fire way to do this. I'm sure this is the way that Thorsten will be typically doing it too...