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Strange Motion Blur Sampling
Posted: Fri Sep 26, 2014 5:59 pm
by profbetis
I know typically people come across a problem and it's fixed by increasing that object's motion blur samples, however this is not that problem.
Firstly, this is an image from a series I'm doing about car wheels in motion. The result is spectacular and exactly what I needed (granted I had to use 128 motion blur samples).
But as I started messing with the kernel's motion blur duration setting, I noticed something strange.
It appears as though octane is taking it's samples during the entire frame, and then just using less of them based on the duration. I think this is a shoddy way of dealing with this. I think that instead (if possible) the motion blur samples should be distributed only amongst the time needed.
Re: Strange Motion Blur Sampling
Posted: Fri Sep 26, 2014 7:20 pm
by Karba
profbetis wrote:I know typically people come across a problem and it's fixed by increasing that object's motion blur samples, however this is not that problem.
Firstly, this is an image from a series I'm doing about car wheels in motion. The result is spectacular and exactly what I needed (granted I had to use 128 motion blur samples).
But as I started messing with the kernel's motion blur duration setting, I noticed something strange.
It appears as though octane is taking it's samples during the entire frame, and then just using less of them based on the duration. I think this is a shoddy way of dealing with this. I think that instead (if possible) the motion blur samples should be distributed only amongst the time needed.
I will check this case
Re: Strange Motion Blur Sampling
Posted: Fri Sep 26, 2014 8:48 pm
by profbetis
Thank you Karba! I know you are busy so I appreciate this. I know a majority of users may not benefit from this, but those of us pushing the renderer to its limits are!

Re: Strange Motion Blur Sampling
Posted: Tue Sep 30, 2014 11:12 pm
by bcravin
Here is a quick test that I ran to show some of the issues that I'm seeing.
Attached are a few stills and a link to a short animation. I'm using Octane 2.06 and 3ds Max plugin.
The scene is simple, it is a small rectangle that is rotated at a high velocity. and then linked to a box that is moving forward is space with high velocity. I have a more complicated scene for a project that I'm working on that actually shows much worse artifacts than this. But this will give you a good idea.
As for motion blur settings: Duration .5 (180 degree film standard).
Motion blur samples: 4 (I saw no difference when going to higher sample rate)
Movable proxy: Checked
vertex motion blur: UNchecked
object motion blur: Checked
https://www.youtube.com/watch?v=LnSuleJ7bMo
Can someone at Otoy please take a looks at this? or at least respond? I've posted about this in a couple other locations with no response.
Thanks!
Re: Strange Motion Blur Sampling
Posted: Tue Sep 30, 2014 11:33 pm
by Karba
bcravin wrote:Here is a quick test that I ran to show some of the issues that I'm seeing.
Attached are a few stills and a link to a short animation. I'm using Octane 2.06 and 3ds Max plugin.
The scene is simple, it is a small rectangle that is rotated at a high velocity. and then linked to a box that is moving forward is space with high velocity. I have a more complicated scene for a project that I'm working on that actually shows much worse artifacts than this. But this will give you a good idea.
As for motion blur settings: Duration .5 (180 degree film standard).
Motion blur samples: 4 (I saw no difference when going to higher sample rate)
Movable proxy: Checked
vertex motion blur: UNchecked
object motion blur: Checked
https://www.youtube.com/watch?v=LnSuleJ7bMo
Can someone at Otoy please take a looks at this? or at least respond? I've posted about this in a couple other locations with no response.
Thanks!
What is wrong with this video?
Re: Strange Motion Blur Sampling
Posted: Tue Sep 30, 2014 11:35 pm
by Karba
profbetis wrote:I know typically people come across a problem and it's fixed by increasing that object's motion blur samples, however this is not that problem.
Firstly, this is an image from a series I'm doing about car wheels in motion. The result is spectacular and exactly what I needed (granted I had to use 128 motion blur samples).
But as I started messing with the kernel's motion blur duration setting, I noticed something strange.
It appears as though octane is taking it's samples during the entire frame, and then just using less of them based on the duration. I think this is a shoddy way of dealing with this. I think that instead (if possible) the motion blur samples should be distributed only amongst the time needed.
I am trying to reproduce the issue.
Could you send me the scene (just with this wheel)?
[email protected]
Re: Strange Motion Blur Sampling
Posted: Wed Oct 01, 2014 2:29 am
by bcravin
Please refer to the still frames from the video that help show the problem
Re: Strange Motion Blur Sampling
Posted: Wed Oct 01, 2014 2:30 am
by Karba
bcravin wrote:Please refer to the still frames from the video that help show the problem
And what is the problem with them?
Re: Strange Motion Blur Sampling
Posted: Wed Oct 01, 2014 5:23 am
by bcravin
If that doesn't look wrong to you, I will post some stills from my current project to better illustrate the issue I'm having. But I keep running into the same issue where object with rotation that are moving in a straight line do not have proper motion blur. They have a weird curved motion blur.
You can see it in this picture I posted a few months back as well. The object is moving in a perfect straight line. no reason for the motion blur to look like that.
http://render.otoy.com/forum/download/f ... &mode=view
Re: Strange Motion Blur Sampling
Posted: Wed Oct 01, 2014 7:55 pm
by Karba
bcravin wrote:If that doesn't look wrong to you, I will post some stills from my current project to better illustrate the issue I'm having. But I keep running into the same issue where object with rotation that are moving in a straight line do not have proper motion blur. They have a weird curved motion blur.
You can see it in this picture I posted a few months back as well. The object is moving in a perfect straight line. no reason for the motion blur to look like that.
http://render.otoy.com/forum/download/f ... &mode=view
Are you expecting straight lines in motion blur of rotating objects? LOL