Motion Blur Problem

[jan_wielert]

Hei Guys, I have still no clue why the motion blur in my scene have this weird effect. Here is the file: https://www.swisstransfer.com/d/84d5...4-46030a1b74ec
It seems like some of the scatter objects have their own movement direction and speed. For the blur the scene is moving and the camera stands still. I need soome avice. Merci!

[bibin_thomas]

It seems that the scattering in the project also has displacement. Maybe you should put all the objects related to scattering in the project into a new empty object.

[bibin_thomas]

Like this, and then just move the "new" object

[jan_wielert]

Like this, and then just move the "new" object

Thank you! Unfortunately the problem still exists. I found out, that it's the Mountain geometry which is causing the issue. If I replace it with a C4D Landscape everything is fine.
Can someone tell me what's wrong with it?

[boyan]

Hey, Jan,

Thank you for the scene file and report. How about: Select your render camera and create a new physical camera. Enable motion blur, set the exposure value, and compare the results. Use camera setting to control the motion blur. I guess it's an intentional camera to use top/bottom movement and to use render settings samples?

Cheers,

[jan_wielert]

Hey, Jan,

Thank you for the scene file and report. How about: Select your render camera and create a new physical camera. Enable motion blur, set the exposure value, and compare the results. Use camera setting to control the motion blur. I guess it's an intentional camera to use top/bottom movement and to use render settings samples?

Cheers,

Hello Boyan, thanks for the reply. Creating a new camera didn't do the trick. Here I uploaded the simplified file: https://www.swisstransfer.com/d/aeb8...d-07b099f97366
It's quiet strange, that the streaks are also appearing on the landscape geometry (on "pure" as well as on the converted). Please see the attached picture for better understanding.

[jan_wielert]

...and maybe it could be partially solved, if I could convert the scatter objects into instances? But it's not pissible, right?

[deyan.hadzhiev]

Hey jan_wielert, the problem in your setup is that you have animated transformation of the "ENVIRONMENT" group, which effectively transforms the polygon objects, which are used as a distribution source for the Scattered spheres. Since the Chaos Scatter object considers its relative position to the scattered distribution source, by not having the Chaos Scatter object use the same transformation as the "ENVIRONMENT" group, you effectively introduce distribution "morphing", which can cause the effect you observe with motion blur.

So to fix this, you have two options:
1. Put the Chaos Scatter object and its distribution sources in a common group (Null object), and then move the whole group in animation as a whole (see your modified example scene I have linked).
2. Instead of animating the geometry - you can animate the camera movement (what boyan suggested). Generally animating only the camera movement has potential to increase your rendering performance with motion blur.

I hope this helps you achieve your desired effect and don't hesitate to ask more question if you encounter problems with the proposed solutions.

[jan_wielert]

Thank you. Still, if I try to replicate this in my file, the effect is there. Could you please check this: https://www.swisstransfer.com/d/87ee...c-a67aa66c0f86
In this scene there is no movement of the Mountain, only the camera. And I put the Mountain in the same null object of the scatter. I'm confused....

[deyan.hadzhiev]

Interesting scene - we will have to investigate further what might be causing this problem. While we investigate, a temporary workaround to your problem would be to make the Scatter object editable object (which should generate an instance object with the instance positions). Sorry for the inconvenience - we will write here when there is more information on this matter.

[jan_wielert]

Alright. Thank you!

[boyan]

Hey, Jan,

Thank you for your efforts. It seems Scatter does not like much of this geometry and generates the extra instances;

However, if you add a connect object, it seems to fix the issue. I will add this to our bug tracking system for future resolution.

Scene file which works in my tests : https://drive.google.com/file/d/1-Od...ew?usp=sharing

Cheers,

[jan_wielert]

Hey, Jan,

Thank you for your efforts. It seems Scatter does not like much of this geometry and generates the extra instances;

However, if you add a connect object, it seems to fix the issue. I will add this to our bug tracking system for future resolution.

Scene file which works in my tests : https://drive.google.com/file/d/1-Od...ew?usp=sharing

Cheers,

Thank you, boyan! The trick with "connect object" did it! The only thing is that if the geometry inside this node is an instance, it should be set as such and not as "render instance".
Still, it would be nice to understand what exactly is wrong with this geometry. My guess is that this exact problem appears on any geometry, but its more or less noticeable as you can see in the post 6.