Vector Pass Issues Tweet

[Jolbertoquini]

Hi Guys,

We did some test with Standalone 3.06 test 3, with Motion Vector, Basically the results is really different of the motion blur rendered with Octane the "internal" mode we use on maya plug and standalone we have same problem after we test the same scene use only motion vector from Arnold we get the same result as the standalone 3d motionblur render.

I attach at this message orbx scene exr renders and a image to explain the case. Please let us know if is settings or something on the software there is fusion but same issues on Nuke and AfterFX.

Best,
JO

[calus]

Yes right, motion vector pass in Octane is a joke,
I guess nobody in Octane team ever tried to use it.

I measured the value of the vectors and found that the distance from the camera doesn't affect vectors.
If 2 Objects have the exact same movement but one in front of the camera, the other very far, they will have the exact same vector ...
This is absurd as obviously the object near the camera need a way stronger motion-blur post effect.

So ok, this is not a vector pass but a velocity pass and we need to take care of the distance from camera by ourself...(z component of the camera space)
So I tried, I divided Vector pass by Zdepth pass and magicaly the post motion blur begin to looks like the rendered motion blur.(also the the ridiculously low values of vectorX(red) and vectorY(green) doesn't help)
but even this way the post motion blur feels very low quality , still very far to the quality of Arnold motion vector pass.
On the other side, Arnold motion vector almost match exactly the Octane rendered motion blur
_

[calus]

ArnolExport.zip

here is the vector pass from Arnold for the same scene, as you can see unlike Octane, far and near sphere don't have the same vactor value.

(331.45 KiB) Downloaded 240 times

screenShot of the Fusion comp showing the technic for dividing the Vector pass by the Zdepth

[abstrax]

Yes, I can confirm that the viewport transformation isn't applied to the motion vector (it seems it was always broken). It's too late for the upcoming test 4 release, but we will fix it with the release after that.

[calus]

Yes, I can confirm that the viewport transformation isn't applied to the motion vector (it seems it was always broken). It's too late for the upcoming test 4 release, but we will fix it with the release after that.

Thanks

[Jolbertoquini]

Yes, I can confirm that the viewport transformation isn't applied to the motion vector (it seems it was always broken). It's too late for the upcoming test 4 release, but we will fix it with the release after that.

Oh ! Sorry we spot a bit late but thanks if we could have sometime would be great!

[annisnaeem]

Hi.
Has this been fixed? I'm experiencing the same issues. I'm rendering out of Blender Octane, and my motion vector pass is doing bizarre things. I'm not sure if I fully understand what Calus was saying above...
I'd really like my motion vectors passes out of Octane to work in Nuke.