Yes each zone has 3 different details levels. High, Normal and Low. This included both vertex info for the geometry plus some fancy texture layer.

Depending how close the zone is depends on the level of detail, except if we have a higher level loaded already then we use that, if it’s a lower level then we need to get hold of the correct level of details.

There is a slight twist to that as based on the texture thing but we don’t need to discuss that.

I have read that document and it is very interesting. I have done some quick maths and at this time I believe my method to be faster. This method boils down to the following facts.

Zones are large you can only ever see a MAX or around 8-12 and normally only 4-6.
All the maths in my method are simplistic. No tree management etc.
I never have to consult the viewable area as I logically know its < n distance and between Da and Db degrees.

I plan to make a document much like the one you sent me and ask people to give me their opinions on the two methods. I think a document would make the comparisons ease for people to see.

Forgot to log on lol! last message was mine!