vray motion blur shutter curve

[jenya.andersson]

Hi All,
It would be really great if we can get a shutter curve for camera motion blur.
As we have found the shutter efficiency spinner not quite giving us the result we are after.

We carried out some testes to match motion blur from are Arri Alexa footage and couldn't get the motion blur to match accurately. (we matched the speed of the disk and set the shutter speed same as the camera)

we shot test footage like this:



However we did mange to get the motion blur to match accurately with in Arnold using the shutter curve and rolling shutter parameter and would love to see this in Vray please.

Would love to map a curve like this to the camera:



Arnold camera settings:




Renderman details on shutter curve
http://renderman.pixar.com/view/moti...depth-of-field
http://renderman.pixar.com/resources...meramodel.html



Thanks in advance

[vlado]

We'll probably not be doing this for now. However it should be possible for you to write a camera plugin that remaps the time values to whatever curve you need. We can get you some examples to get started with.

Best regards,
Vlado

[jenya.andersson]

Thanks Vlado for your quick reply,
Can this be done through max-script? (sorry not a good scripter)

[vlado]

No, it would be a C++ plugin.

Best regards,
Vlado

[jenya.andersson]

Thanks Vlado, C ++ is way over my head . Just thinking long term would be possible to integrate this into vray, in the future? As this is a must for vfx getting the cgi integrated into the live action back plate.

Also is possible to achieve the rolling shutter effect, as you can see from the e.g images above. The circle wheel lines are curving. In the second image the vertical lines are skewing.

Thanks

[vlado]

As this is a must for vfx getting the cgi integrated into the live action back plate.

I don't know, no-one's requested it so far. If it was a must, I'm sure the question would have come up long ago. We'll do it if there's enough interest, of course, but for the moment it's somewhat hard to justify integrating this into V-Ray. For you specifically, like I said we can do a separate plugin if you think it's really needed.

Best regards,
Vlado

[jenya.andersson]

I don't know, no-one's requested it so far. If it was a must, I'm sure the question would have come up long ago. We'll do it if there's enough interest, of course, but for the moment it's somewhat hard to justify integrating this into V-Ray. For you specifically, like I said we can do a separate plugin if you think it's really needed.

Best regards,
Vlado

Sure i understand vlado no problemo,
Yea it would be cool to get a plugin if its not too much trouble, we can do further Rnd to see if its helping.
I think the plugin will also be helpful for the guys working with live action footage, to get that cinematic motion blur look.

[jenya.andersson]

Hey Guys
After further testing we couldnt match Arri Alex motionblur footage in Vray. We need more accurate controls to control motion blur in Vray. To minic a more realistic motion blur.

You can see that the lines are curving, that related to rolling shutter.

- Shutter efficiency
Control is too simple we need ramp control, posted above


- Rolling shutter
We need some kind of rolling shutter control

Can see from the examples motion blur is looking very different

Arri Alex footage


Vray motion Blur:


PS the red dot is there to match speed ignore

Thanks

[jenya.andersson]

Any updates? on plugin progress?