[jessermeyer]

I've worked on several. You haven't heard of them because none of them shipped due to issues with commercial engines (in particular Unreal Engine 4).

They are very difficult to use if the game play semantics are complicated and require lots of interaction with world state or world geometry. If you're making a common FPS, they are great.

[nomel]

> They are very difficult to use if the game play semantics are complicated and require lots of interaction with world state or world geometry.

Could you give an example? I’m trying to understand what the limits look like. It appears to be trivial to you, but for someone outside of game design, I can’t imagine what those might be.

[jessermeyer]

We almost never hit technical limits in the renderer, streaming systems, etc. Instead, we found that pushing gameplay systems beyond the prototype stage would require more and more effort, as we'd encounter deep engine bugs, or the tooling simply did not cater to our use case.

We ended up implementing more and more tooling outside the engine, and there comes a point where UE4 became a IO/Rendering system. We'd've been happier if the engine were modular in design from the get-go.

[nomel]

Sorry, I think we're stuck in a loop.

> we found that pushing gameplay systems beyond the prototype stage would require more and more effort

I understand that you're saying that some systems exist that can't work. I'm trying to understand what those systems would look like, and how the user would see it as being different. Do you have an example of the system/mechanic that can't work?

[jessermeyer]

Not at a high level that is easy to express in a HN post, sorry. It's one of those "the devil is in the details and there are a lot of details".