Author Topic: support Motion blur for change topology objects like fluid  (Read 15903 times)

2016-06-21, 09:51:58

Siahpoosh

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as i found corona is not supporting motion blur for objects that change topology like fluid objects , its really needed , hope corona team add this in next release.

tnx

2016-06-21, 11:15:11
Reply #1

Christa Noel

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long time ago I remember that this is an already planned feature.
but I still vote for this :D +1!

2016-06-21, 16:06:44
Reply #2

Siahpoosh

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i think it will be solve if corona read 'v' attribute for velocity and use it for motion blur .

2016-06-23, 09:35:28
Reply #3

JCdeBlok

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I think this is already in, a few weeks ago I was rendering fluid meshes generated using PhoenixFD in Corona and MB worked great.

edit:  See this horribly failed simulation setup, notice the small droplets having correct MB:  https://www.dropbox.com/s/fvkzr4na4ub6xsd/topo_mb_example.mp4?dl=1

2016-06-23, 14:34:53
Reply #4

maru

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Just to clear this as there seems to be some confusion over this topic:
1. Motion blur WILL WORK fine on deforming objects (e.g. you take a sphere an add an animated noise modifier to it - the number of vertices/faces remains the same through all the frames)
2. Motion blur WILL NOT WORK on objects where topology is changing (e.g. you take a sphere and animate it so that the number of vertices/faces changes during the animation; like metaballs)

JCdeBlok - that video, how is it made? Is it rendered with Corona? This probably shouldn't work. :)
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2016-06-23, 14:42:20
Reply #5

pokoy

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Just to clear this as there seems to be some confusion over this topic:
1. Motion blur WILL WORK fine on deforming objects (e.g. you take a sphere an add an animated noise modifier to it - the number of vertices/faces remains the same through all the frames)
2. Motion blur WILL NOT WORK on objects where topology is changing (e.g. you take a sphere and animate it so that the number of vertices/faces changes during the animation; like metaballs)

JCdeBlok - that video, how is it made? Is it rendered with Corona? This probably shouldn't work. :)

I remember rendering Water splashes with changing topology in Brazil which also wasn't supported but for some reason it worked, although results were inconsistent and would change slightly when re-rendering. Maybe there's enough information from animation subframes for the motion blur to work with short shutter speeds but fails for anything exceeding a certain value.

2016-06-24, 11:54:11
Reply #6

Christa Noel

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2. Motion blur WILL NOT WORK on objects where topology is changing (e.g. you take a sphere and animate it so that the number of vertices/faces changes during the animation; like metaballs)
I remember rendering Water splashes with changing topology in Brazil which also wasn't supported but for some reason it worked, although results were inconsistent and would change slightly when re-rendering.

this thread getting more interesting, where here I still cannot use MB with water simulation but never try another changedtopology objects.
look at those small droplets , how did you do that JCdeBlok?

2016-06-29, 11:04:37
Reply #7

JCdeBlok

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Just to clear this as there seems to be some confusion over this topic:
1. Motion blur WILL WORK fine on deforming objects (e.g. you take a sphere an add an animated noise modifier to it - the number of vertices/faces remains the same through all the frames)
2. Motion blur WILL NOT WORK on objects where topology is changing (e.g. you take a sphere and animate it so that the number of vertices/faces changes during the animation; like metaballs)

JCdeBlok - that video, how is it made? Is it rendered with Corona? This probably shouldn't work. :)

Well.. :) I used PhoenixFD to generate the fluid sim and set it to 'mesh' output.. which I guess stores the velocity in a data channel. Then simply rendered in Corona with MB enabled.. it just worked!

2016-06-29, 16:14:50
Reply #8

maru

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That's interesting. I wonder what Ondra would say about it. :)
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2016-06-29, 19:41:05
Reply #9

Siahpoosh

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yes i think its possible, for me it works in a scene with crowd , which have lot of changes in topology by born/kill agents during the time , and then i cached all of them into xMesh file , and got a nice motion blur and never got a error like this in corona until now its not working with my mesh which is exported from houdini via alembic.

2016-06-29, 19:42:52
Reply #10

Siahpoosh

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Ondra , could you tell us what is velocity attribute in corona ? is this v ?

2016-06-30, 10:43:47
Reply #11

Ondra

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I dont understand the question...
Rendering is magic.How to get minidumps for crashed/frozen 3ds Max | Sorry for short replies, brief responses = more time to develop Corona ;)

2016-06-30, 15:29:31
Reply #12

maru

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I don't understand the new question either.
The original one was: why does motion blur sometimes work with changing topology, for example with fluid simulations?
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2016-07-01, 09:13:47
Reply #13

Ondra

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because the topology does not actually change in the shutter open time span ;) There are only countably many discrete topology changes in each simulation, it is possible to miss them - then everything will work
Rendering is magic.How to get minidumps for crashed/frozen 3ds Max | Sorry for short replies, brief responses = more time to develop Corona ;)

2016-07-01, 10:39:44
Reply #14

Siahpoosh

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I dont understand the question...
for example in Arnold render there is an option to use custom velocity call "Motion Vector Source" :


i think for this type of objects its better to use their own velocity which is stored in simulations instead of calculating that with render engines , i try to create v velocity for my mesh and it works with other render engines like vray . so want to know is there any way to doing something similar like this with corona ?