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Motion Blur Issues

Posted: Tue Jun 04, 2024 5:27 pm
by DJTravisty
Is it normal for the first frame to take over an hour or two to render/ load motion blur if you start at frame 400 of 15000? After the first frame (400) render times go back to normal.. Is there a way around this? Set the timeline to start at 400? That possible solution a real pain with alembics and simulations


Separately, I have a camera that snaps to one location to another. That first frame after the camera move is understandably crazy with motion blur. But if I animate the 'Enable' from 'off to on' for that first frame after the snap, Octane breaks and spits out white frames.

Re: Motion Blur Issues

Posted: Tue Jun 04, 2024 7:12 pm
by frankmci
An hour or two for the first frame is not normal if your average frames take from seconds to a few minutes. Are giant particle systems involved, or huge geometry morphing caches? Highly detailed volumes being dynamically meshed maybe? More detail about the construction of the scene will help find the culprit.

Keying the motion blur on and off will only get you so far, since to properly calculate the blur, several frames of position and vector data need to be considered. You might try to pause the camera motion at the new location for the same duration as as your motion blur frame cache +1 to give the algorithm time to catch up after blur is reenabled. Or just pause without any keyframing of the blur; it will take slightly longer to render the transition frames, but probably worth it, not having to mess with another variable.

Re: Motion Blur Issues

Posted: Tue Jun 04, 2024 10:35 pm
by aoktar
Keying motion blur effect will cause wrong calculations. Also having some content which needs to be calculated that will cause long preparation times like dynamics/particles/etc...

Re: Motion Blur Issues

Posted: Tue Jun 04, 2024 11:27 pm
by DJTravisty
I need to get in the habit of using a Stage Object and multiple cameras to solve most half my issues. For now I just keyframed the shutter time down to 0 for those first frames.

For this scene I have one high poly main character that is driven by over 150 pose morph meshes. I want to send a version off c4d RNDR render farm but I'm worried the motion blur loading times will take way too long for the render farm.

Re: Motion Blur Issues

Posted: Wed Jun 05, 2024 2:01 am
by jayroth2020
Looking at your still frame, do you even need motion blur? You might be better off going ReelSmart here...

Re: Motion Blur Issues

Posted: Wed Jun 05, 2024 4:11 am
by DJTravisty
Its nice for the lips mainly.. And a few metal parts that fly in, but besides that not really. Do you think RSMB is better than the built in AE motion blur?

Re: Motion Blur Issues

Posted: Wed Jun 05, 2024 5:30 pm
by jayroth2020
It has been in my experience