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ue4plugins / MobuLiveLink

Plugin for MotionBuilder that send data to Unreal Engine
MIT License
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Jitter #6

Closed TheExiledLeader closed 6 years ago

TheExiledLeader commented 6 years ago

When setting up a follow camera in UE4 to follow the data from MoBu Live Link there is random jitter in the skeleton joints on the UE4 end. This is not present when streaming the same exact data from the Maya Live Link.

DrHibbitts commented 6 years ago

Do you have an example of the issue or a reproduction I can use to test?

Normally if there's Jitter it's because something isn't evaluating fast enough so I'd check your framerates in Motionbuilder and in Unreal as well as looking at increasing the sample rate in the device.

Thanks, Dave

TheExiledLeader commented 6 years ago

Here's the documentation I've taken while doing testing.

Issue: Jitter on the mesh during movement when streaming from MoBu to UE4 through Live Link Appears to be from individual joints not whole mesh Character with separate mesh per joint, each mesh jitters individually Character with single mesh with skin weights, whole mesh jitters Visible with static camera More obvious with camera follow More prominent with faster movement (playback speed x5 in MoBu) Tried with plotted and non-plotted animation Tried at different frame rates in MoBu timeline Tested all UE4 Live Link refresh rates

UE4 System fps - ~90 MoBu System fps - Min: ~48, Max: ~90 during playback MoBu Evaluation rate - Min: ~350, Max ~625 during playback

Set up the follow cam using a spring arm third person setup to follow useful joints Follow Pelvis Used snap to socket Used “set location” Follow Root: Constrained Root to Pelvis in MoBu Used snap to socket Used “set location” Used Camera Streaming with Live Link Constrained follow camera in MoBu Smooth playback in MoBu Jittery playback in UE4

Issue persisted on both types of follows on both Joints in several setups No setup seemed to improve/worsen the jitter Jitter gets better with lower playback speed and with a larger distance between camera and actor

Tested the same FBX file streaming from Maya No Issues Same camera follow BP

And this is the BP I'm using the drive the spring arm location: setcam_location

TheExiledLeader commented 6 years ago

ybot_maya_gif

ybot_mobu_gif

DrHibbitts commented 6 years ago

Damn, that's a lot of jitter. Something seems very wrong there.

Is this file sharable? If possible please email me at david.hibbitts@epicgames.com and I'll look into it. I've just tested a similar setup in 4.20 + Mobu 2017 and it's looking smooth.

It could be something to do with that rig that I've not encountered before, or something off in the setup of the device.

Thanks, Dave