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Weird motion blur issue

Posted: Fri May 26, 2023 2:47 pm
by dogindagrass
I've been using the legacy motion blur option because I would like to have 'afterimages' for my characters when they're moving fast. Although, in this file I've been working on it has been rendering it backwards.
Instead of trailing behind for roughly 18 frames, it's been rendering out about 4 seconds into the future and the characters fallow it.
I've never seen this happen before and putting it in a test file with the same settings had it working properly. is there anything that could have caused this to happen? And how do I fix it.

The settings I'm using
Motion Blur On (Checked)
Sub-Frame Motion Blur (OFF)
Frame Count: 6


Frame Skip 3
Start Opacity 50
End opacity 5
blur radius 6

Re: Weird motion blur issue

Posted: Fri May 26, 2023 4:48 pm
by Greenlaw
I don't use the built-in motion blur but for a stepped motion trails effect, you might consider using duplicate layers and then using graduating levels of transparency or colors for each step.

This is easier and faster if you first pre-render your animation and then import the footage as an image sequence. Then you can simply duplicate the layer multiple times and offset them in Sequencer, and apply the different settings on each layer.

How you offset and layer the footage determines how direction and look of the effect. You might also experiment with blend modes for the trailing layers.

Re: Weird motion blur issue

Posted: Fri May 26, 2023 4:49 pm
by synthsin75
If you've moved the layer in the sequencer that can mess up motion blur timing.
Quick fix is to select the layer and frame zero and use the menu command Animation>Set Layer Start Time.

Re: Weird motion blur issue

Posted: Fri May 26, 2023 6:37 pm
by dogindagrass
Yeah, thanks!
That was my problem, I shifted the time of my layer which messed up with how the blur happened.
I reset the time offset and rejiggered my key-frames and got it working properly.

Using duplicates might be better, I was worried about how cost-effective it could be and would really ramp up export time.

Re: Weird motion blur issue

Posted: Fri May 26, 2023 7:11 pm
by Greenlaw
It shouldn't if you pre-render the animation and then use stacked image sequences instead becasuse Moho won't have to recalculate any deformations then.

Normally I do this sort of thing in comp because it's more efficient, but you can sort of use Moho in a similar way if you don't have a compositing program.