Mo Blur Not Working

[pali_rao]

Hi

Im not sure why this is happening, but I have a car on a racetrack and the wheels of the car and the track have been to animate and keyframed at frame 0 and frame 27. I can play the animation and verify that meshes do move.

I've put the place in the timeline to frame 14 and have a VRay physical camera with mo blur enabled and the shutter speed set to 1s.

When I do a production render, there is no mo blur at all.

Im sure it's a setting I've overlooked, but not sure what or why. I added a geo tag for displacement of the tyres but that's about it.

Mo blur has worked, but something has changed.

Im using C4D 2023 and VRay 6

Any help appreciated!
Thank you

[sirio76]

Hi

Im not sure why this is happening, but I have a car on a racetrack and the wheels of the car and the track have been to animate and keyframed at frame 0 and frame 27. I can play the animation and verify that meshes do move.

I've put the place in the timeline to frame 14 and have a VRay physical camera with mo blur enabled and the shutter speed set to 1s.

When I do a production render, there is no mo blur at all.

Im sure it's a setting I've overlooked, but not sure what or why. I added a geo tag for displacement of the tyres but that's about it.

Mo blur has worked, but something has changed.

Im using C4D 2023 and VRay 6

Any help appreciated!
Thank you

If you can share the scene I’ll look what's wrong in your setup

[deyan.hadzhiev]

Hi pali_rao, using a shutter speed of 1s is quite slow. You have not shared your document settings, but presuming you are using the defaults, you are actually using 30 frames per second. So in order for the physical camera to properly render the motion blur for this interval, you actually need to set duration in the Overrides to the number of frames that would be covered by your camera shutter speed. If my presumption of using the default of 30 FPS is right, then you need to change the "Duration (frames)" value to at least 30 frames. Please note that the number of geometry samples still remains 8, which may be low for this setup - so generally I suggest either considering faster shutter speed or increasing the geometry samples (apart from matching the motion blur duration with your camera shutter speed).

As an additional hint - using the global geometry samples with high values may result in high memory usage. If you only need the high geometry samples for the wheel rotation motion blur - I suggest using the VRayObjectPropreties tag, which would allow you to raise the geometry samples only for part of your object hierarchy (like the wheels), while you could keep the global geometry samples low (usually 3 or 4 is sufficient if your camera and objects move linearly).

[pali_rao]

Thank you for the quick response Deyan. Yes you are right, I am using 30fps as default. I have increased the duration in the camera overrides to 30 - still no motion blur in the production render, and I have tried increasing the shutter speed to 1s.

More worryingly, I have a very simple scene a cube animation and I can Redner using VRay Production Render and I get mo blur. I then stop this, and immediately re-launch, removing the previous render, and there is no motion blur despite nothing changing in the settings - please find the scene attached.

[deyan.hadzhiev]

Hi pali_rao, by increasing the shutter speed I meant setting higher values there. A value of 30 means a shutter speed of 1/30s.
For the scene you sent - I can't seem to reproduce your issue - the motion blur is always present, at least until frame 40, because afterwards there is no animation. Are you sure you are starting the production rendering and not the interactive one (we don't currently support motion blur in interactive rendering)?

[pali_rao]

Hi Deyhan

Im using VRay 6 and C4D 2023 if that helps at all?

Is it possible to send you a zipped copy of my scene file so you can check please? Im really stuck and not sure why it's not working. Plus the cube issue seems to be a bug for my set up and I can render and get mo blur and then render again with no blur.

Im using Vray > Start Production Render to see the result.

Any hope greatly received as I desperately need to get these final renders done...

Thank you

[aleksandar.kasabov]

Hello pali_rao,

Could you please send us your scene in question with all assets for it so we can have a look? You can open a support ticket via our contact form and attach the scene there. Thank you.

[pali_rao]

Im sure this is my error, but Im not sure where Im going wrong.

Please see attached two files - If I set the shutter speed to either 1s or 1/1000s in the physical camera, I get the same render which is not right - any clues?

[boyan]

Hey, Pali,

Thank you for the report. I think you are using a global camera override option simultaneously with V-Ray physical camera. Could please use one of them? Use the global option when you do not intend to use V-Ray physical camera.

Enable the mo blur option inside the "DOF and mo blur" tab part of the V-Ray Physical camera. It is located right on the General tab.

Cheers,

[pali_rao]

Hey Boyan! Thanks for the clarification there - I've turned off the global settings in the render settings now and Im using just a VRay Physical Camera with Mo Blur enabled for the settings. It still does not show up in the prod render - please see attached images for details.

[boyan]

Hey, Pali,

Do you have a velocity render element, and what is the information there? Don't expect to see velocity in the first and last frame of the animated object.

Cheers,

[pali_rao]

Hi Boyan

No I don't have a render velocity element. Im sticking to the middle of the motion, but NOTHING I have done all day has produced any motion blur. Even moving the background of the scene at 100m/s produces no motion blur in the production render, with a keyframe at 0 and 70 and setting the pointer at a mid frame with physical camera shutter speed at 1/2s product no mo blur.

[pali_rao]

Is there a YouTube video ro something on how to set up mo blur in C4D please? I can't find anything recent. I've got the Vray for C4D course from 3d render and beyond, but in there they have almost the same example and just turn on mo blur in the camera and it works. I worked professionally as a photographer before becoming a digital artist, so Im very familiar with camera settings.

[sirio76]

Is there a YouTube video ro something on how to set up mo blur in C4D please? I can't find anything recent. I've got the Vray for C4D course from 3d render and beyond, but in there they have almost the same example and just turn on mo blur in the camera and it works. I worked professionally as a photographer before becoming a digital artist, so Im very familiar with camera settings.

Hi, I’ve received your file, I’ll look your scene as soon as I complete a render!

[sirio76]

I’ve done a few tests, there are several things to improve but none of them affects the motion blur issue. As soon as I use a simple cube instead of the car the MB do work, I still do not understand where the problem is.. I’ll look more in depth later, it’s very weird..