Hi, thanks Pappenheimer,
Each colored segment gets loaded when needed so that more resources can go into the look of the environment.I havnt built with the block method for ages but yeah, if that approach was taken that would be the go.

The above shot just displays the extent and componants of the level and most componants past the observatory are full of back ground effects like insect swarms and bettles scurrying about plus dynamic light effects and possilble contact scenarios with the inhabitants.

When game starts, only the mountain face componant is loaded then when the player gets near the entrance to the sub terrainian worlds the entry componant is loaded and when the player enters the air lock, the mountain and entry componants are deleted while the access tunnel is loaded and so on.