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dwburman
10-21-2012, 03:49 PM
Hi, I'm trying to figure out a post-effect motion blur workflow, but it looks like the motion buffers are seriously screwed up when using instances. Is there a trick to get it to work?

Here's the Y motion buffer without the instances turned on:
108668

Here's the Y motion buffer with instances turned on:
108667

Here's an experiment using DP filter to combine the Y and X buffers into something Reel Smart Motion Blur can use:
108665

Incidentally, if I just use LW's built-in Vector Blur image filter, the blur is all wrong too and looks like a zoom blur originating in the lower right quadrant of the image.

Is there a way to fix or work around this?

108666

I fogged it (Case 51998)

dwburman
10-23-2012, 10:44 AM
Is this a known issue? Can someone confirm it?

lertola2
10-23-2012, 07:35 PM
There was one point a year ago when I tried to get something out of lightwave that would work with Reel Smart Motion Blur. Despite a lot of advice from very smart people on this list I was never able to get it to work properly. Even non instanced geometry has the same problem I think. I would love to have someone in the know post a clear explanation of how to get to get motion vectors out of lightwave and into aftereffects with RSMB. It is still a mystery to me.

dwburman
10-24-2012, 03:42 PM
I got an email back about my bug report and the problem didn't happen on the latest build, so I hope 11.5 is ready before I need to render. :)

Here's a video showing my experimental setup for a LW to RSMB Workflow:


http://youtu.be/vUX6F7-BQnA

dwburman
10-24-2012, 03:50 PM
double post

sukardi
01-01-2013, 02:53 PM
Hi,

Just checking to see if anyone know if this problem has been fixed.

Thanks

dwburman
01-01-2013, 05:47 PM
I've been told (on my bug report ticket) that this issue wasn't occurring in newer internal builds, so it should be fixed for LW11.5.

sukardi
01-01-2013, 06:08 PM
I am still having problems with 11.03.

I suppose we just have to wait for 11.5...

sukardi
02-01-2013, 03:44 AM
I have tested in LW 11.5 and there seems to be no difference.

Can anyone confirm that motion x and motion y buffer still does not work correctly for instances? Does anyone knows any work around?

LW 11.5 is awesome all around but I really need to figure out this problem (or if there actually is a problem). Really appreciate any feedback.

Thanks in advance.

VermilionCat
02-02-2013, 10:27 AM
Hey, what's goin on... this is unnerving issue for a long time... Isn't this fixed in LW11.5??

Celshader
02-02-2013, 11:31 AM
Hey, what's goin on... this is unnerving issue for a long time... Isn't this fixed in LW11.5??

Random thoughts:


LightWave 11 instances never delivered the correct motion vector information.
As far as I know, 11.5 does not fix it.
Our compositing pipeline for LW11 Instances at work is no different than the one we used for the volumetric-based DP_Instance, which can show up in almost every render buffer except for Motion Vectors.


More random thoughts:


FiberFX motion vectors were added in 10.1, but lost in 11.0.x.
FiberFX motion vectors were restored in 11.5. So that motion vector issue has been fixed.

sukardi
02-02-2013, 03:38 PM
Hi celshader,

Thanks for your thoughts. Can you elaborate how you deal with instances in compositing if it cannot use motion vectors. Does this means that you have to fo the motion blur during render? Practically all my scenes have instances...

Cageman
02-02-2013, 03:59 PM
Hi celshader,

Thanks for your thoughts. Can you elaborate how you deal with instances in compositing if it cannot use motion vectors. Does this means that you have to fo the motion blur during render? Practically all my scenes have instances...

For things lying flat on the ground, you can create a new scenefile that only renders motionvectors, that does not contain any instances at all. We have some shots where there are tons of small things lying on the ground, and doing it this way works fine!

For larger things, such as trees etc, the only way to get something that kind of works, is to, again, create a new scenefile and place spheres or boxes where the instances are and render thouse with MVectors. In comp, you then use the alpha from the instances as a mask and "project" the motionvectors onto the instances. This doesn't give you exact MBlur, but close enough to make it work.

This technique was used a couple of times for smoke-effects we did in Max in order to get motionvectors for it.

Celshader
02-02-2013, 04:00 PM
Hi celshader,

Thanks for your thoughts. Can you elaborate how you deal with instances in compositing if it cannot use motion vectors. Does this means that you have to fo the motion blur during render?

Yes, for those elements that use instances. For example, on a creature show using LightWave 10.1 we had a creature kicking up instanced straw (DP_Instance). The creature was rendered without motion blur, and motion vectors handled the creature's motion blur in comp. The instanced straw was rendered with in-camera motion blur and mixed into the comp.

Mixing real and post-process motion blur should get a bit easier with LightWave 11.5, since 11.5 offers the ability to render centered motion blur with its "Shutter Open" offset option in the Camera panel. Nuke's Vector Blur could be shifted, but Reel Smart Motion Blur in After Effects was always centered no matter what. Now LightWave's in-camera motion blur can be centered, too.

sukardi
02-02-2013, 04:25 PM
Thanks a lot Cageman, Celshader.

You guys really knows your stuff...

Cageman
02-02-2013, 04:46 PM
Thanks a lot Cageman, Celshader.

You guys really knows your stuff...

:)

Another thing that you can do, IF you have enough RAM and no animation on your instances...

Use a Python-script called "Python Bake Instance". This script will turn your instances into real geometry. It works like this.

1) Select the instance source object(s). These are the objects that are being instanced.
2) Run the script (you can add it to a shortcut key or add it to your menu).
3) Wait

This will give something that will work with motionvectors, but, if your instances are animated (like lots of leaves blowing in the wind through the nodal instancer using a texture to drive the animation, as an example), it will not output the animation. If your instances are driven by MDDs, it should work (I have not tested that though).

VermilionCat
02-02-2013, 09:28 PM
So it's technically impossible to implement Motion Vector for LW instance?