Could anyone explain their function to me? I'd really like to know and can't find the exact use fo them.

Looking at where occlusion planes are placed in vanilla skyrim dungeons, it looks like they're just there to cover up little holes so you see black instead of the fog color.

ow then I'm using them wrong but might explain an issue I have.

THanks

Occlusion planes/cubes are used to cause anything on the opposite side from the player to stop rendering. VERY useful if you have, say, a huge wall with lots of stuff behind it but you'd never be able to see it until you're on the other side. Saves oodles of frames. Also useful to sandwich an occlusion plane in between a first and second floor of a large building for the same reason. Just don't cover the accessible stairway with it

Check the cities, you'll find cubes under many of the major structures. Though not all, and certainly a few more could be liberally placed without causing a problem.

lol I thought (no idea why) that it would prevent creatures from passing so I'd put them around my new castle to prevent dragons from flying through .. to be honest I saw most of them still but the waterfall on the other side of a towere gave problems and some angles of the dwemer towers too .

thx

btw IS there a thing that prevents dragons from flying through my castle?

You could create a collision plane that extends around the roof of your castle, but that's not dragon specific of course.

Dragons go where they please. Nothing you can do about that as far as I know.

hmmm it kill immersion a bit if he flies right through you castle though.

ow collision planes.. well not much flying except dragons so I might try that.