I've started learning Houdini recently and I'm bringing some simulations into UE4. Up until now I've mainly been doing short bursts and such so I haven't had the need to mask out the edges as I can keep it contained within the timeframe. However, I've moved towards bringing looping animations into unreal, but for this I obviously need to mask out the edges. I've attempted to use the volume multiplication technique presented on the pluralsight tutorials, however I find that this reduces the resolution of the smoke/pyro. So I was wondering what other methods you guys use and can suggest in order to get a nicely masked simulation.

Thanks in advance!