Motion blur problem with foam

[jstrob]

I rendered soome foam for the first time. I have some frames where the motion blur become very high like if everything is exploding. I rendered this on my render farm. Many exploding frames were coming from the same node but one of them was a different node. And the same nodes also rendered correct frames...

it was in this build: phoenixFD_adv_21010_max2014_vray_30_x64_24277

correct mblur


exploding mblur:

[Ivaylo Katev]

this means you are using backburner, not DR?
very probably the node is not to blame, perhaps it just gets broken cache files. you can test this rendering on local machine the same frame.
can you share the scene and one cache file that produces the problem?

[jstrob]

edit: I was writing here that I could not render foam anymore with lates nighlty... that was not rue, sorry.. I just forgot in my RPManager to activate athmospheric effect.

I will prepare a more simple scene to see wath's happening with motion blur and foam on my farm. I use Deadline.

[jstrob]

I have another problem with this scene now.

The splashes are cut when motion blurred. see pictures:

here is the simulator mesh without splash,. the motion blur is correct on this alone:


here is my splash without mblur: it looks ok.


But here is the splash with mblur. It looks like if it is cut in half. It appears like that on a few frames when the water enter the room.


you can see a video here (look at the very first frames):
http://www.phylacterecola.com/strob/...m_v003_out.mp4

And here is the scene with the cache for the problematic frames. (I just remove the characters).
http://www.phylacterecola.com/strob/...lurProblem.rar

[Ivaylo Katev]

what build are you using? there was a bug in the mb that produces similar result, but is already fixed.

[jstrob]

I uise 24293. (14-03) Was it supposed to be fixed in this one?

[Ivaylo Katev]

yes, it should be. this means the bug is not the same. ok, i will look what happens

[jstrob]

Ok thank you Ivaylo.

[Ivaylo Katev]

ok, i think i found it, but tell me your max and vray version to send you a build, the fix will be not in the nightlies tomorrow.

[jstrob]

Max 2014 sp4 64 bits(I am about to instal sp5)
vray 3.00.03 official build

[Ivaylo Katev]

ok, i found your email, the file is sent

[jstrob]

thanks,

so it looks now like if there is no motion blur at all on the splash. Only the reflection and refraction are blurred with this dll.

You can try to render fram 92. This one render quite fast. just remove GI and set low global dmc sampler settings. And you can see the result.

[Ivaylo Katev]

ok then, i hope tomorrow can do this

[jstrob]

I am still rendering this shot. My average task time is 3 hour because i have so many bubble. It looks like a bubble bath now very cool. the motion bltur problem was really only at the begining of the water pouring. Like if the bubble were trying to get velocity from the mesh and they could not catch it well at the edge or something...

[Ivaylo Katev]

the mb problem is only at the beginning because it is related to inexact calculation of the bounding box, here you have no problem because it affects only the zones near to the bounding box borders
btw your geometry is rendering very slow, i don't know why. i'v removed all the geometry from the scene to make the experiments, and then the foam renders much faster.