3d starts shaking after you go further than 32000 in xyz from the center of the world(0,0,0)
ie
x=10
y=32000
z=10
as go further, the shaking oscillates progressively faster proportionally.
at around 32000 the shaking starts(about 1 pixel across screen), and at 100000+ the shaking is about 3 or 4 pixels oscilation across the whole 3d screen.
I dont know if this is a GLBasic bug, or an OpenGL common issue.
Either way, at this point it is something to be careful of, not to stretch too far.
I found this issue by trying to represent a position as 1 foot, and create a rather large world...time for some scaling.
might be a problem, because internally OpenGL uses 32 bit floats.