The author probably should be able to suggest a standard unit of
movement, or even a movement method, but the actual movement method
and unit of movement is a browser issue. If I want to run around the
web pretending im a bee, then moving into a space where movement is
defined as taking "steps" as if I were on the moon is pointless. Also,
If my machine is slower than the authors, his steps of .1 units would
be perhaps too small for my browser to handle smoothly, although thats
mostly my problem.
I think the idea of being able to suggest a movement mode is nice, but
not necessary, and mostly an option that should be left available for later
Locating and scaling objects in the scene is a relatively trivial operation.
See VanDam et al.