A groundplane to organise things from is certainly the path of least
resistance. We always use the ground (both as a surface and gravitation
field) as reference when moving about. Simulating ground makes it easy for
people to quickly grasp a world.
Anectdote: Go to a mirror, look into your eyes, and tilt your head. You'll
see that your eyes will rotate to stay level till you tilt about 20
degrees. Physically, we have a auto-horizon calibrating visual system!
I for one would love to explore possibilities and vertigos of a
non-groundplane based world, but I do think that the ground is a safe bet
if you don't have a particullar reason for abandoning it. If someone
develops a QD3D browser/navigator, which allows six axes of movent, I'll
jump on it.
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Torbjoern Caspersen casper@due.unit.no
http://www.stud.unit.no/~casper/
Student of Architecture
at the Norwegian faculty of technology, NTH, Trondheim.