when you re going to do a track on a track editor you could have an option to build a track just in one environment, two or three
this means if you are building a track in the woods (valley) you could direct the track some where in the dessert (canyon)
so lets put thus into perspective
one environment is 1.0
two environments are 1.5 or more (in this case one envi is 0.75)
three environments are 2.0 or more (in this case one envi is 0.66)
this means that if you would combine two environments it wouldn t mean that you would have two environments in one editor, it means that there would be 1.5 (or more)environment in one editor
same goes for the three environments
the numbers mean how much space does the environment or environments take
one environment takes 1.0 space
two environments combined take not 2.0 space but 1.5 space (or more)
three environments combined takes not 3.0 space but 2.0 space (or more)
if you don t understand this
just ask
i think this is an "epic" idea
The way they have TM coded, the numbers aren't really that important, IMO. Not to say that it isn't a good idea, tho. If anybody's here (and there has to be) that's played the original TM, remember the back of the box? There was some HUGE track on there that linked all 3 enviros. That would be pretty awesome to seamlessly slide from one to another and back again...you think the possibilities are endless now? Just wait until we get SmoothTrackin! 
Or something. LOL I dunno, it's early and my brain doesn't work.