Yes it’s unfortunately a known problem - you need to keep temporal sampling at 1, really. But spatial sampling can be whatever you like.

I tend to find that setting temporal at 1 and spatial at 64 gives fantastic results. And most of the time I use 32 for spatial. It depends on the scene.

I also have found that legacy ray tracing deprecated, with hardware enabled, gives the absolute best quality. Lumen just isn’t there yet, and path tracer still has a lot of issues.

Btw I’m not sure if the groom issue with temporal samples will be fixed in upcoming UEs. I am on their board a lot and on GitHub and definitely haven’t seen it coming down the pipe. :)

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virtualfilmer.com | youtube

Oh and btw it has nothing to do with the live link plugin. It’s UE itself.

Bassline has answered this a few times btw, and you might want to search his awesome thread for it? Although I’ve found it’s a difficult issue to search for answers on, for some reason.

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virtualfilmer.com | youtube

It should be fixed in UE5.2 but If you are using UE5.1.1 you can try this here : https://forum.reallusion.com/535847/UE5-Exploding-Hair

Awesome, thank you so much for your help guys.

I had the same problem, and I got nowhere with answers. But I learned about the Nvidia DLSS/DLAA plugin that is a plugin that works with movie render queue. It upscales and renders super fast--I mean real time fast. I used to render with anti-aliasing 1 64 and the console variables. A one minute animation would take about 2 hours. With DLSS, that was down to 4 minutes or less. And guess what? The hair physics works flawlessly. https://www.youtube.com/watch?v=frQOAptM6Yg

Here is the link to get dlss...
https://developer.nvidia.com/rtx/dlss/get-started

and here is a brief tutorial on how to use it
https://www.youtube.com/watch?v=tp-33N3YCV4

Here is an example of using DLSS with hair physics in unreal 5.1.1 
This render took less than 5 minutes.
https://www.youtube.com/watch?v=juuH3z8_96I

I am thinking of buying LIveLInk, but it is hella pricey! $745...yikes. Anyway, I only want it because I can't tweak animations or poses that I export from Iclone8 into unreal. Or can I? Besides livelink, is there a way to build a control rig to allow for animation tweaks once you import the cc4 fbx into unreal?

@raitan , cool stuff ! 👍

Live Link is free for Indies ! https://www.reallusion.com/iclone/live-link/unreal-engine/indie.html

And Control Rig is coming for CC4 ...