[Opensim-dev] What does SizeZ = 256 mean in a Region.ini file?

[Ai Austin]

I understand SizeX and SizeY are there to specify the default region 
size or a varregion size... but what does the SizeZ mean and what 
effect has it?

The three entries are now place din every region.ini file created.

It defaults to 256 yet I can travel up to 3000m for example, and 
below 0m for deep water builds.

http://opensimulator.org/wiki/Varregion  does not mention SizeZ.