Motion blurred Fur in Mental Ray broke.

[Jozvex]

And on top of that, the MR bulit in fur doesn't calcuate raytrace shadows correctly from the opacity of the fur,

Yeah I hate that!

[Jackdeth]

With more digging, it seems to be almost a half frame behind of the source object. I'm trying to see if there is some way to offset how the "time" node is applied to only the fur. My gut is telling me that this might not be possible.

[Jozvex]

I have no doubt you've thought of this, but what if you just composited a fur layer and fur shadow layer over your object with offset time?

But still, yes it needs fixing.

[BillSpradlin]

You can create a seperate time node for the fur only and then apply an offset to that to with a simple expression and give that a shot. I don't know if that will fix the problem, but maybe it will provide a temporary work around.

[Jackdeth]

I haven't got into time expressions, but I did a poor-mans version of that by adding a second object that has it's animation offset by .5, but that didn't fix the problems. It seems to be more of a non-linear issue, almost as if its moving backwards instead of forwards, but I can't really tell.

What a piece of crap.... :D.... but I refuse to let some "software" defeat me. There is always more than 1 way to skin a cat, but some are more bloodier than others.... Its now time to pull out the chainsaw....



**EDIT** Victory is mine....errr...good enough. Using our own custom MR Fur shader combined with a 2D MR Blur Shader seemed to do the trick. A good fix for me, but not for everyone else. I hope Ducan scopes out this thread and looks into this...

[Kabab]

http://www.alias.com/eng/support/maya/index.jhtml <== report bug button :)

[slipknot66]

I tried to make a test, just to understand the problem, Maya crashed..lol damn slow computer cant wait to get my new one.oh.. and btw i didnt knew that hydraulx was the studio behind the Godsmack Video clip, thats cool:twisted:

[Jackdeth]

I tried to make a test, just to understand the problem, Maya crashed..lol damn slow computer cant wait to get my new one.oh.. and btw i didnt knew that hydraulx was the studio behind the Godsmack Video clip, thats cool:twisted:We didn't just do the effects for Godsmack, my brother and I also directed the video too. If you watch the MTV Making of the Video you'll see both of our ulgy mugs the whole time. The Rock was a really cool guy, and Kelly Hu was really fun as well. You can check out our directing stuff at www.brothersstrause.com (http://www.brothersstrause.com)

[slipknot66]

Thats really cool, Congratulations, thats a nice work.:)

[Jackdeth]

An Update.


The 2d blur shader is helping, but it's vectors are different than the surface object's vector, so its not perfect. The best thing about the 2d blur shader is that the fur isn't lagging or being occluded by the surface object any more as it deforms, so now my fur no longer flicker or dissappear. I tired to render this in the Maya Renderer, but the z-depth issues ruin any chance of getting that to look good. Not to mention that a Maya motion blur doesn't exactly line up with MR 3D motion blur.

I'll report this bug to Alias, and maybe by version 10 they'll have it fixed. :rolleyes:

[slipknot66]

you are right, this thing is really not working, here is a test i did, a 10 frames 360 rotation, and i got weird results. Im using motion blur exact deformation.
http://img146.exs.cx/img146/7158/furblur9jo.th.jpg (http://img146.exs.cx/my.php?loc=img146&image=furblur9jo.jpg)

[Lyr]

Don't know if you tried this or not, but by default maya seems to leave the Export Custom Motion vectors option off in the mental ray globals. If you haven't yet turned it on do so and see if that fixes the problem. I'd try it myself but I do not have access to a seat of unlimited today, TD is using it.

[slipknot66]

Yes, you are right, you need to turn the Export Custom Vectors and Custom Motion on, then it works just fine:thumbsup:

[Lyr]

Glad to hear it works. It makes more than a little mad that such critical global settings get left off by default.

[Jackdeth]

Hmmmm, I'll try that one tomorrow. If it works, I'll have to buy you a beer next time you're in LA.

[Jackdeth]

Well, no beer for you. ;) It still renders all wrong.

Slipknot, are you sure its rendering fine for you? Do a simple test of a sphere moving fast on one axis with exact MB with a default fur discription.

[slipknot66]

Well, here is the test image, as you said, the first one is using the linear Transformation, the second one is using the exact deformation.I guess that the first render i did was nice, because it was not a fast movement, but now, as you can see there are some weird things behind the fur.Im using the export vector/motion feature. I even tried to render using the standalone version, but i got nothing different, the problem still persists.
http://img144.exs.cx/img144/802/furballlinear6bk.th.jpg (http://img144.exs.cx/my.php?loc=img144&image=furballlinear6bk.jpg)
http://img144.exs.cx/img144/4118/furballexact2np.th.jpg (http://img144.exs.cx/my.php?loc=img144&image=furballexact2np.jpg)
I dont know what i did, but the first render was really cool, nothing wrong with the fur, but now as you can see, the problem is back.

oh.. and about the beer, well if you come to Brazil one day,we can drink some beers here.. no problem..:buttrock: :p ..lol

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