I too think the absence of a global coordinate system may confuse world
designers.
R> 1) The base coordinate system should be in the VRML standard, not ad-hoc
R> 2) +Z should be up from ground plane, NOT into the screen
R> 3) X-Y should define the ground plane
R> 4) Should use the right hand rule
R> 5) rotations should be additive, body centered, NOT about fixed axis set
R> 6) +Y should be forward in body-centered coordinates (i.e. if you
R> build a geometric model of a vehicle, you use the convention that the
R> +Y axis is the front!)
Have I overlooked something? I thought the VRML spec (maybe somtimes
not clear enough) defines a right handed coordinate system with a
horicontal x-z-plane (x to the right, z towards viewer) and the y axis
pointing upwards. For example the fields of Cube (x=width, y=height,
z=depth), top/bottom of Cylinder, and the default cameras, looking
from (0, 0, 1) horicontally into the world make that clear.
It just needs one rotation about the x-axis to define models with an
x-y-plane coordinate system, z pointing up, which I consider simpler
than suddenly changing (poss. implicitly given parts of) the spec.
Just my 2 Groschen.
bye,
Michael Pichler
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