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Motion Blur saved in floating point format?
show user profile  Nanne
Hello mates!

I've heard somewhere that floating point file formats do not support Motion Blur. So rendering with Motion Blur and saving it as an OpenEXR would resolve in a file output without the Motion Blur.

Is this true, or is it an old restriction? Is there a way to circumvent this?

I'm working on a 15 seconds animation and I would like to give it a try with real 3d ray traced motion blur with mental ray. But I have to render in layers to do compositing afterwards, so I want to work with 16-bit float OpenEXR.


Kristoffer Helander
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read 725 times
9/8/2011 3:37:26 PM (last edit: 9/8/2011 3:37:26 PM)
show user profile  Dan Andersen
Floating point exr works just fine with motion blur
read 708 times
9/8/2011 5:03:53 PM (last edit: 9/8/2011 5:03:53 PM)
show user profile  Error404
I'm not quite sure what you are saying. Are you referring to motion vectors?

EXR has no problem holding floating point data, motionblur or no motionblur does not make any difference, it's just pixels.

Maybe it's something with MentalRay doing motionblur as a post process that is clamping the image? If that's the case, then it doesn't matter what format you use, it will be clamped if it's a problem with mentalray's motionblur process. I don't know, just a guess, I don't even know if mentalray does moblur as a post process or not, but that's the only thing I can think of that might result in clamped images when motionbluring. -

read 697 times
9/8/2011 9:12:30 PM (last edit: 9/8/2011 9:14:39 PM)
show user profile  Bolteon
the only time when you can't get motionblur into a floating point image is with depth values / z-depth that isn't clamped.

outside of that, everything else can be motionblured and in floating point.

(good luck using mental ray with motionblur in general though... *giggles*)

-Marko Mandaric

read 692 times
9/8/2011 9:14:21 PM (last edit: 9/8/2011 9:14:21 PM)
show user profile  Nik Clark
I'm pretty sure you can just render to EXR when using motion blur in MR.

Whoops, double post. D'oh!

read 690 times
9/8/2011 9:14:47 PM (last edit: 9/8/2011 9:44:28 PM)
show user profile  Nik Clark
Thought I'd give it a go, just to check.

16-bit EXR rendered in Max, loaded in Composite. 32-bit worked fine as well. Motion blur seems to be there.

Edit: Spelling. Dur.
Edit2: Yup. Bolte is right. Be prepared for long renders using motion blur in mental ray if you want it nice and smooth.

read 681 times
9/8/2011 9:49:25 PM (last edit: 9/8/2011 10:05:29 PM)
show user profile  Nanne
Nice to see you working in Composite there Nik :) Hope you like it.

Thanks for all the imput and testing for me. When thinking about it, I think it was Image Motion Blur that didn't work in floating point, not ray traced. I just read something similar about the RPF-format, when using the RealPixel option or something like that.

Yepp, I know it is slow, but since it's such a short animation I thought I might have the time. I used Vector Motion Blur in Composite for previous project, but it doesn't handle complex motions very well and it looks strange with very extreme motion blur.

Cheers mates!

Kristoffer Helander
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read 656 times
9/8/2011 11:55:16 PM (last edit: 9/8/2011 11:55:16 PM)
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