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Chaos Corona for 3ds Max => [Max] Feature Requests => [Max] Resolved Feature Requests => Topic started by: Siahpoosh on 2016-06-21, 09:51:58

Title: support Motion blur for change topology objects like fluid
Post by: Siahpoosh on 2016-06-21, 09:51:58
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
Title: Re: support Motion blur for change topology objects like fluid
Post by: Christa Noel on 2016-06-21, 11:15:11
long time ago I remember that this is an already planned feature.
but I still vote for this :D +1!
Title: Re: support Motion blur for change topology objects like fluid
Post by: Siahpoosh on 2016-06-21, 16:06:44
i think it will be solve if corona read 'v' attribute for velocity and use it for motion blur .
Title: Re: support Motion blur for change topology objects like fluid
Post by: JCdeBlok on 2016-06-23, 09:35:28
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
Title: Re: support Motion blur for change topology objects like fluid
Post by: maru on 2016-06-23, 14:34:53
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. :)
Title: Re: support Motion blur for change topology objects like fluid
Post by: pokoy on 2016-06-23, 14:42:20
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.
Title: Re: support Motion blur for change topology objects like fluid
Post by: Christa Noel on 2016-06-24, 11:54:11
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?
Title: Re: support Motion blur for change topology objects like fluid
Post by: JCdeBlok on 2016-06-29, 11:04:37
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!
Title: Re: support Motion blur for change topology objects like fluid
Post by: maru on 2016-06-29, 16:14:50
That's interesting. I wonder what Ondra would say about it. :)
Title: Re: support Motion blur for change topology objects like fluid
Post by: Siahpoosh on 2016-06-29, 19:41:05
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.
Title: Re: support Motion blur for change topology objects like fluid
Post by: Siahpoosh on 2016-06-29, 19:42:52
Ondra , could you tell us what is velocity attribute in corona ? is this v ?
Title: Re: support Motion blur for change topology objects like fluid
Post by: Ondra on 2016-06-30, 10:43:47
I dont understand the question...
Title: Re: support Motion blur for change topology objects like fluid
Post by: maru on 2016-06-30, 15:29:31
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?
Title: Re: support Motion blur for change topology objects like fluid
Post by: Ondra on 2016-07-01, 09:13:47
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
Title: Re: support Motion blur for change topology objects like fluid
Post by: Siahpoosh on 2016-07-01, 10:39:44
I dont understand the question...
for example in Arnold render there is an option to use custom velocity call "Motion Vector Source" :
(https://support.solidangle.com/download/attachments/19202357/image2016-4-15%2013%3A33%3A23.png?version=1&modificationDate=1460720004000&api=v2)

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 ?
Title: Re: support Motion blur for change topology objects like fluid
Post by: Ondra on 2016-07-01, 10:43:40
better question is, is it possible in 3dsmax? Does any other renderer support it? because AFAIK 3dsmax does not allow storing arbitrary data in meshes... :/
Title: Re: support Motion blur for change topology objects like fluid
Post by: Siahpoosh on 2016-07-01, 16:46:00
i thought its possible with alembic files
Title: Re: support Motion blur for change topology objects like fluid
Post by: JCdeBlok on 2016-07-03, 08:30:25
better question is, is it possible in 3dsmax? Does any other renderer support it? because AFAIK 3dsmax does not allow storing arbitrary data in meshes... :/

Have a look at this, it allows for per-vertex extra data: http://docs.autodesk.com/3DSMAX/15/ENU/MAXScript-Help/index.html?url=files/GUID-102D2769-720E-4F73-9973-13AE18A65E90.htm,topicNumber=d30e361174
Title: Re: support Motion blur for change topology objects like fluid
Post by: Rotem on 2016-07-03, 17:18:27
Supported in VRay as far as I can remember, if the mesh contains velocity data. I'm not sure where it's looking for that data since 3dsmax doesn't define any data storage convention for vertex velocity information, but I remember it working with stuff like Realflow meshes, PRT files meshed with Frost, Alembic, etc.
Title: Re: support Motion blur for change topology objects like fluid
Post by: Siahpoosh on 2016-07-05, 12:44:05
in vRay there is a solution to render alembic with correct velocity for fluid objects with vRayProxy , it can import Alembic directly inside that and then it will load velocity for rendering motionblur.
maybe we can have something similar like that in corona ?
Title: Re: support Motion blur for change topology objects like fluid
Post by: Ondra on 2017-03-21, 14:10:55
Duplicate: https://corona-renderer.com/bugs/view.php?id=1304
Title: Re: support Motion blur for change topology objects like fluid
Post by: aneta on 2022-07-18, 10:13:09
Hello,

I was wondering if this has ever been resolved?
Is there any way to create motion blur from flip simulations without converting to vray?
I tried assigning velocity attributes to vertices before exporting to abc but without any luck..
Title: Re: support Motion blur for change topology objects like fluid
Post by: tradstown on 2022-08-22, 22:59:17
I'm interesting in this too. Corona team, can we get some feedback about this please?