In Search of Tips for Keeping the UI out of my renders when Motion Blur is on

Currently getting the UI rendering into my setup. I’ve seen it before and it seems to be tied to motion blur. Turn off MB and the renders are fine. Turn it on and it’s all wrecked.

But what if you need motion blur? I’m doing particles and there’s not another way to get motion blur.

Anyone know any tricks to make this bug go away? Cos this suuucks.

Flame 2023.1 - Linux.

It’s an interaction between MB and transparency. And maybe multiple outputs. The two workarounds I use are:
Do your dissolve up with a matte external to the action, feeding it into the layer matte input. Maybe a gmask node and a full frame mask fading up. Maybe a dissolve between white and black. Many ways to do it.

The problem with the transparency is when it comes off of 100% So If you make your transparency in action 99.9% going to 0% that might work.

Apparently there is a fix in the latest release. But some facilities haven’t upgraded yet.

oops. didn’t notice it was for particles. I don’t know If these will work for particles because there is usually a expression for the transparency. Hmmm


Thanks Andy for summoning the UI Djinn. UI just showed up in my last render, just now, after behaving all day otherwise. (2023.1 Mac)

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This may be purely my superstition about this problem, but I find that grabbing the entire batch and bypassing everything, unbypassing, and then rendering immediately without looking at the result of anything can sometimes resolve the issue temporarily.

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Fred answered it here: You've Been Burn'd Ep22: So Simple, Yet So Far Away.. AKA 'Fuque You Flame' - #12 by fredwarren


Looks like I may be SOL since there’s no way to manage this within a particle it would seem.

Since the particle system hasn’t been updated in a while, this may be a cost effective solution:


I’d put $20 on that thing CRUSHING a P620 on Flame particle renders.

Come On GIF by HBO Max

This has been fixed in 2023.2 Update


Andy, can you output motion vectors from action and use batch motion blur? I haven’t tried this with particles, but in theory…
I basically do this most any time I need motion blur these days (though I haven’t encountered the UI render thing.)