[danielbarla]

I'm not an expert on the topic either, but from similar discussions I've followed, the answer tends to be that out of the box and with the base settings, an engine like UE5 will be optimised for certain use cases. Different genres will have different specific needs, and may require your developers to do a lot of heavy lifting to make the engine performant under their specific conditions. A good example might be sim racing titles, which generally have the player moving a lot faster than the default scenario for an engine (which is mostly a slow-moving FPS, for example). At these relatively high speeds, the default antialiasing methods may result in serious graphical artifacts, and at the rate at which physics needs to be calculated (90-300 hertz) the default physics of the engine may be less useful, and you're forced to implement your own from scratch. That's not to say it's impossible, but you're opting out from a lot of the engine features, or in some cases, it's actively making your life hard.

[robswc]

Awesome answer. Thanks for those examples, makes a ton of sense!

I just assumed in 99% of cases, you could just "tweak" Unreal but if its issues with core components of the engine... I could see why an engine from scratch may work better.