Hallo folks,
and again, thanks everybody for the answers. They convinced me to keep analyzing my issue, since, from what you wrote, it was just non-sense for OpenLevel to be the cause of my stutter: by the book, OpenLevel should indeed LOAD EVERYTHING before putting the player in the world. And indeed, that’s the case; on the opposite, I’m finding that using LoadStreamLevel, as @Hexavx was mentioning, it’s always causing stutters (wondering how much data can you actually stream in real time without stuttering… I even tried just showing a looping animation while I “stream” the level, and that too, it just stutters… heavily!).
So the stuttering wasn’t caused by Open Level. The stuttering was caused by this particle effect:
Having one of these in the level, no big deal, but once I started having more than a couple, et voila’ stutter stutter. The longer the more instances of the effect I had in my level. After fiddling with Niagara, I found this solution: enabling Warm Up, by setting to 5 seconds the “Warmup Time” in the Niagara System Properties:
So something completely unrelated to the loading. However, silver lining: this development hiccup brought me to study the loading system quite in depth, and I’ve discovered so much about stuff I was doing wrong. After “cleaning” my system, I reduced my initial loading times from more than one minute (1’13" to be exact) to 17 seconds overall. Win! 