[herpdyderp]

When I'm in the demo, it lags to <30fps while I'm on any part of the city. However, once I leave it for the water (with the whole city in view), it surpasses 60fps. Why would that be? I expected having the whole city in view would drop the FPS rather than raise it.

[zem]

without looking at the code, I can guess that things like occlusion and visibility calculations are a lot harder when you are within a city than when you know the entire city is in the same direction relative to the camera.

[bavell]

LOD optimizations are pretty common and standard too

https://en.wikipedia.org/wiki/Level_of_detail_(computer_grap...

[zem]

I don't think LOD optimisations are enough when you are in the middle of a solid with complex holes in it, but that's a detail (no pun intended) - there are doubtless lots of other techniques you can apply. but my larger point was whatever optimisations you make, performance when looking at the entire city from the outside is likely to be better than looking at some part of it from the inside.