Re: Coordinate Systems

Jeffrey A. Holmes ([email protected])
Tue, 23 May 1995 12:29:59 +30000


On Mon, 22 May 1995, Gavin Bell wrote:

> The current VRML spec assumes that Y is up. That should be stated
> explicitly; it is an unfortunate oversight. The descriptions of Perspective
> and Orthographic cameras, and all of the primitive shapes would have to be
> changed if the up direction isn't Y. Since no amount of arguing is going to
> resolve this issue, I suggest we take the easy way out and use the
> conventions described above (Y up, Z is out, distances are meters, rotations
> are radians) that are implicit in the existing VRML spec. And to avoid
> rehashing this issue in the future, we should add the above description to
> the VRML 1.0 spec.
>
Agree, this wasn't my expectation, so it took a bit of trail & error to
figure out which axis was which since width, height and depth don't have
an implicit mapping to people without a 3D modeling background. An
explict statement is needed to make the standard accessible to casual users.
(since most of web space is built up by casual users, I think it's clear that
wrl space will be a minor eddy without them).
_________________________________________________________________________
Jeffrey Holmes * Magnet Interactive Studios, Inc. * http://www.magnet.com
work: [email protected]
http://www.magnet.com/~jah/index.html
personal: [email protected]
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